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Tandy's Little Wonder, 

The Color Computer 


A complete history and reference guide to the CoCo and all 

related hardware, software, and support sources. 

by EG. Swygert 

( ^ ^ y published by 

FARNA Systems 


Tandy's Little Wonder 

the Color Computer: 1 980- 1 99 1 

(and still going strong into the next century!) 

written & edited by F.G. Swygert 

Copyright 1993 by F.G. Swygert All rights reserved. 

Published by FARNA Systems 
P.O. Box 321, Warner Robins, Georgia, 31099-0321 

'Allcinitc addrcii for author and publisher u: 
CoCoBock, c/o F-Swygert, Rl 4 Box 145, Loctville, S.C 29070 
Pleaie ananpt to conUet ihrough miin addreti (P.O. Box) fint. 

Tandy's Little Wonder 


Tandy's Little Wonder 

the Color Computer 


The following individuals have made contributions directly or indirectly 
to the content of this book : 

Frances Calcraft 

Lee Duel] 

Thomas Fann 

Art Flexser 

Marty Goodman 

Frank Hogg 

Don Hutchison 

Carmen Izzi Jr. 

M. David Johnson 

Bob Kemper 

Dave Myers 

Bob Montowski 

Alfredo Santos 

Kelly Thompson 

Jordan TsvetkolT 

Rick Ulland 

Brian Wright 

Glenside Color Computer Club 

This book is dedicated to "The Rainbow Magazine", which ceased publication this year, and to all the 
pioneer CoCo programmers and supporters. Without all of you, the CoCo would not be alive today. 


All brand/trade names copyright their respective owners. 

No part of this publication may be reproduced or quoted 

without written permission from the publisher. 

All design and editing performed by F.G. Swygert. 

Printed in U.S. by CopyMasters, Warner Robins, GA. 

First Edition. Publication Date: 20 April 1993. 

Copyright 1993 by F.G. Swygert. 

Printed in Australia with permision by 

REMCOMS, 11 Corcoran Cres, Canungra, QLD 4275 

page 2 Tandy's LitUe Wonder 

Table of Contents... 

Writting Conventions 






C.oCo Hardware Prices: 1980-T991 


CoCo Clones 


Dragon Systems/Tano Dragon 






Color Basic 




Compiled BASIC 


Converting Between BASICs 


Other DECB Programmmg Languages 





Machine/Assembly language 


Binary & Hexadecimal Conversions 


Microwares' OS-9 





User Groups and Clubs 


Current Vendors 


Annual CoCoFests 




Current Publications 


A Tribute to "The Rainbow" Magazine 


The CoCo Library 


Past Magazines 


Technical Reference 


Video Display Devices 


Mass Storage 




Expansion Devices 


Miscellaneous Devices 


Hardware Upgrades & Modifications 

ROM Upgrades 


RAM Upgrades 


Upgrading the Keyboard 


The Hitachi 6309 CPU 


Putting It All In One Case 



General Procedures/Tools 


General Trouble Shooting 


MC6809E CPU 


MC682 1/6822 PIA 


MC6883 and 74LS783/785 SAM 


MC6847 and MC6847T1 VDG 




Disk Controller and Drive Repairs 


RS-232 Pak Repairs 


Multi-Pak Intrface (MPI) Repairs 


Power Supply Repairs 



The "Colour" Computer Down Under 9 8 

The "68xxx" Story 99 

Two Boys and the CoCo 1 

Frank Hogg and Frank Hogg Labs 101 

About FARNA Systems 1 04 

Color Computer Users Guide 106 

Serial Interface 107 

Cassette Intaface 107 

Joystick Interface 107 

RGB Interface 108 

Cartridge Connector 108 

ASCn Character Codes 108 

BASIC/Extended/Disk Error Codes 109 

Bank S witched ROM Paks (Activision) 1 9 

CoCo 1 (D&E board) 110 

CoCo 2 (American made) 1 13 

CoCo 2 (Korean A, B is similar) 1 15 

CoCo 3 117 

Multi-Pak Interface (large) 1 19 

Multi-Pak Interface (small) 1 20 

FD-501 Disk Controller 121 

Chip Placement Guides 1 22 

Block Diagrams: GIME and MC6809E 1 24 

The following have paid and/or contributed for these ads 
and continue to play an active role in support of the Tandy 
Color Computer. Please let them know you appreciate 
their continued support! 

FARNA Systems 125 

CoNect 125 

Color Systems 126 

Infinitum Technology 127 

BDS Software 128 

Spectro Systems 128 

Infinitum Technology 129 

JWT Enterprises 130 

INDEX 131 


The author and publisher extends their thanks to Tandy. 

Tandy's Little Wonder 

page 3 

writing conventions used in this book.... 

In the course of writing, some standards were set so as not 
to confuse the reader. 

* Hardware modifications, upgrades, and repairs are 

referred to throughout this book. At times, the references 
given may not seem clear. They are written in such a way that 
a person with some understanding of electronics and the 
CoCo can easily figure out what to do. If you do not 
understand the directions, you probably should not at- 
tempt the operation alone... get help! THE AUTHOR, 

* All references to hexadecimal addresses are written as 
"&Hxxxx". The "&H" is used to precede the actual hexa- 
decimal value when poking into memory to let the computer 
know the value will be in hexadecimal. Some other texts use 
a dollar sign ($) in front of a value to mark it as being 
hexadecimal, others use an asterics (*) or don't mark it at all, 
as eight bit hexadecimal values usually contain numbers and 

* When Radio Shack Usts an item mentioned in their 
catalog (especially parts), the part number will be listed in 
parentheses. This is not to encourage patronage of Radio 
Shack, but there is a Radio Shack in or near almost every 
town across the U.S. One would be better served to find an 
electronics parts store with a better small parts stock then 
RS, or mail order parts from one of the following; 

All Electronics Corp. 

P.O. Box 567 
Van Nuys, CA 91408 

Order phone 1-800-826-5432, call for catalog. Minimum 
order is $10 plus $3.50 shipping and handling. 

Mouser Electronics 
2401 Hwy 287 North 
Mansfield, TX 76063 

Phone 817-483-4422, call or write for catalog. 

Digi-Key Corp. 

P.O. Box 677 

Thief River Falls, MN 56701-0677 

Order phone 1-800-344-4539. No minimum order, mini- 
mum shipping charge of $5 (no shipping if order over $25). 
No Motorola chips listed, but will supply non-listed items if 
available. Volume discounts for orders over $100. 

Jameco Electronics 
1355 Shoreway Road 
Belmont, CA 94002 

Order phone 415-592-8097, call for catalog. $20 minimum 
order plus 5% shipping and handling. Catalog usually has 
some IC pin-out information and RAM/EPROM cross ref- 
erence... good reference source. 

* The following abbreviations are used: 

A/L - Assembly Language 
ANSI - American National Standards Institute 
ASCII - American Standard for Computer Information In- 

BASIC - Beginners All-purpose Symbolic Instruction Code 
BPS - Bits Per Second 
CCx - Color Computer, x = 1, 2, or 3 
CMOS - Complimentary Metal Oxide Silicon (chip con- 

CoCo - Color Computer 

CPU - Central Processing Unit (actual processor chip) 
DECB - Disk Extended Color BASIC 
DOS - Disk Operating System 
DRAM - Dynamic RAM 

EDTASM or EDT/ASM - Editor/ Assembler, usually the 
Tandy product 

EMAIL or E-Mail - Electronic Mail 
EPROM - Electronicly Programmable Read Only Memory 
GIME - Graphics, Interrupt, Memory Enhancement (chip, 
in CC3) 

GUI - Graphic User Interface 
IC - Integrated Circuit (a "chip") 
I/O -Input/Output 
M/L - Machine Language 
MPI - Multi-Pak Interface 
MS - Milli-Seconds (millionths of a second) 
MS-DOS - Microsoft Disk Operating System 
NMOS - Negative Metal Oxide Silicon (chip construction) 
OS - Operating System 
OS-9 - Operating System (for the 680)9 
PIA - Peripheral Interface Adapter 
PCB - Perforated Circuit Board 
P/S or PS - Power Supply 

RAM - Random Access Memory, usually meaning DRAM 
ROM - Read Only Memory 

RS - Rat Shack. . . er. . . Radio Shack (division of Tandy Corp.) 
SAM - Synchronous Address Multiplexer 
SECB - Super Extended Color BASIC 
SIG - Special Interest Group 
SP - Slot Pak (also used for Slot Pak II) 
VDG - Video Display Generator 
VOM - Volt and Ohm Meter (multimeter) 
WYSIWYG - What You See Is What You Get 
(and probably others not listed!) 

page 4 

Tandy's Little Wonder 

Introduction. . . 

Alfredo Santos, December 1990 

While skimming througti the pages of a popular Color Computer magazine recently, my thoughts traveled back through 
the 12 years of Color Computer history. Back to a time when there was NOTHING. I recalled the events leading 
up to my introduction to this wonderful machine. It seems like only yesterday... 

Christmas morning 1980: Pam, my wife, must have known that I was very interested in getting a computer because, 
there, under the tree was the new Mattell Intellevision!? Pam bought that machine due, in part, to the computer 
capabilities the unit would have with a keyboard console, scheduled for release in the spring. After several days of 
gunning down waves of aliens, we both suffered from blurred eye sight, blistered fingers, lack of sleep, and video 
game bum out. Spring seemed so far away. 

A couple weeks after Christmas, I came across an ad in the New York Daily News for a new Radio Shack computer 
which, like the Intellevision, had game cartridge capabilities, an important feature because, if I didn't like computing, 
I could always go back to cleaning up the galaxy. For the refund price of the Intellevision (sorry Pam) plus another 
$ 1 50, 1 had enough money to purchase the new TRS-80 Color Computer. I celebrated the arrival of an early "spring". 
It was January 9th, 1981. It seems like only yesterday 

This proj ect was, to say the least, a labor of love. Every attempt was made to ensure an accurate account of the Color 
Computer's evolution. Extensive use of various computer magazine articles and ads were used as the basis for "dating" 
events. This "dating" method was used because most of us probably heard about various developments through these 
sources. Keep in mind, however, that sometimes ads canprecede product availability by as much as a month or more. 
Those of you who ordered the very first "Super 'Color' Writer" program from Nelson Software know what I mean. 
Other information sources included printouts and files from old bulletin board sessions, telephone interviews, and 
correspondence with various users. 

Before starting, let mejust say that, while looking through thenumerousbackissues for ColorComputer information, 
a strange thing started happening. Remember that frustrated feeling, of the early years, when YOU looked forColor 
Computer information and none could be found? It all started coming back to me 

Francis G. Swygert, March 1993 

Al graciously allowed me to use his existing text which was written for submission to The Rainbow Magazine. Rainbow 
decided not to print it, so Al released it to the public over Delphi (a major computer database). Als' format and style 
were used pretty much intact for the history portion of this book, though heavily edited and added to in places by 
myself The original text only went up to June of 1 986. All history text after that date and all additional information 
was written by myself (except where noted) . Many thanks goes to Al and the other contributors ! I can also echo Als' 
opening statement: this project was definitely borne out of a love for the little computer we affectionately call CoCo.. 

It is also important to remember just how this text is written. This was not intended to be a definitive history. Indeed, 
it is the authors' belief that the CoCo is far from being relegated to history as of yet. Instead, the history portion is 
more of an overview of what has happened in the life of the CoCo over the years, almost a "time line" type of 
chronology. The entire book itself is a complete CoCo reference book... the "CoCo bible", so to speak.. 

Don't let the past tense used in the text fool you. It was deemed the best way to present the majority of the history 
and was used throughout for uniformity. Many of the later products were still available and supported by the authors 
and distributors at the time this was written. They simply don't get enough response to maintain advertising costs. 
So go ahead and write- ask for information! The only cost will be a stamp- is that to much for your CoCo? 

Tandy's Little Wonder page 5 

CoCo History 

From Birth to the Present... 


The initial Tandy/Motorola connection occurred sometime 
in the mid-70s when the two were invited by the U.S. 
National Weather Service to assist in developing a "weather 
radio" system. In 1977, a year after starting talks with 
Motorola about the possibility of designing a low-cost 
home computer that could be hooked up to a regular TV set, 
Tandy was invited to participate in an agricultural experi- 
ment. Project "Green Thumb", as it was called, would employ 
information retrieval to give farmers data, updated hourly by 
computer. Terminals used in this project were developed by 
and sold by Radio Shack in conjunction with Motorola. 
Terminals were distributed to 200 farms in Shelby and Todd 
counties, Kentucky. The "Green Thumb" network was spon- 
sored by the National Weather Service, U.S. Department of 
Agriculture, and the University of Kentucky. 

By late 1977, Motorolas' MC6847 Video Display Genera- 
tor chip was developed. Although it was unclear if the VDG 
came about because of project "Green Thumb" or Tandys' 
search for the "low-cost" home computer, in 1978, when it 
was married to the MC6808 CPU, the Color Computer was 
bom. This "prehistoric" Color Computer, however, con- 
tained to many chips to make it affordable for Tandy's 
anticipated target market. Motorola solved this problem late 
in the year by replacing the network of chips which made up 
the memory management circuits with its newly developed 
MC6883 Synchronous Address Multiplexer (SAM) chip. 

In December of 1 979, about a year after production began on 
the MC6809 microprocessor, reports circulated that it 
would be Microsoft, and not Motorola, that would write the 
Basic interpreter for the new "TRS-90". The name TRS-90 
was eventually dropped in favor of a much more "colorful" 

THE FIRST YEAR (Jul '80 - Jun '81 ) 
On July 31st, 1980, two months after unveiling their TRS- 
80 Videotex terminal, Tandy publicly displayed its three new 
computers for 1981: the TRS-80 Model III, the TRS-80 
Pocket Computer and the TRS-80 Color Computer. In 
September, the Color Computer started appearing in 
Radio Shack stores. It sold for $399.00 and came with 4K 
RAM, 8K Microsoft Color Basic 1.0, a 53 key calculator 
type keyboard, built-in video modulator to allow connecting 
to any television, RS-232 interface, a 1500 baud cassette 
interface, joystick connectors, and a slot where Program 
Paks could be inserted. In BYTE magazine's October issue, 
an article speculated that of the 3 new Radio Shack machines 
the TRS-80 Color Computer would probably create the most 
interest in consumer markets. Steve Odneal and Wayne 
Day, in the market for machines at this time, purchased 

page 6 Tandy's Little 

Color Computers and yes, Virginia, some jumpered C- 
boards were sold. Tandy, meanwhile, was rumored to have a 
quality control hold on the Color Computer following sev- 
eral reported failures after only a few hours of operation. 

'68 Micro Journal published the first data sheets for the 
new MC6883 (SAM) chip in November, but there were few 
Color Computer owners out there to read it. Radio Shack, at 
the same time, released the first Color Computer software. 
This ROM-Pak cartridge software included Chess, Check- 
ers, Quasar Commander, Personal Finance, and a Diagnostic 
Pack. By the time December rolled around, there was a 16K 
upgrade available from Radio Shack, Which would be re- 
quired for the delayed Extended Color Basic ROM, which 
was only a month away from introduction. 

If the Color Computer you got as a Christmas gift was your 
first ever computer, you were probably unaware that the 
"Getting Started with COLOR BASIC" manual accompany- 
ing the early machines contained only 13 of the scheduled 
24 chapters. Radio Shack explained, in the December issue 
of its TRS-80 Microcomputer News, that when the ma- 
chines were ready to ship, the manuals weren't! Rather than 
keep the Color Computer from customers, they sent what 
was available. It was probably more a case of not wanting to 
lose out on Christmas sales that prompted the decision to 
ship with incomplete documentation. With the only avail- 
able information being found between the covers of the 
unfinished "Getting Started with COLOR BASIC" manual, 
the first year was like being in the Dark Ages for the small but 
hardy band of early Color Computer owners. 

The place to look for information was either from your local 
Radio Shack store (probably the person who sold you the 
computer) or from Tandy's customer service. Salespeople, 
unless they were also "computer people", could offer little 
if any information. If you were lucky enough to find a 
salesperson with computer know-how, chances are it was 
Model I/Z-80 know-how. No help there. Customer service 
in Fort Worth, on the other hand, had plenty of information, 
and was only a toll-free call away. Unfortunately, Raymond, 
Martin, and Kathy wouldn't tell you much more than what 
was in your manual. Another dead end. 

One of the first books detailing the internal workings of the 
6809 was published in late 1980. Authored by Dr. Carl 
Warren, "The MC6809 Cookbook", contained all the 
information required for assembly language programming. 
Unfortunately it preceded the first Color Computer editor/ 
assemblers by about 8 months and this book was pretty much 

Computer magazines, at this time, were filled with articles 
and reviews about every computer except the Color Com- 
puter. When anything did appear, it was usually comparing 
the Color Computer (unfavorably) to the Atari 800. Review- 
ers pointed to the "chicklet" keyboard, limited screen dis- 


play (16 X 32), inverse lower case, and small RAM size as 
areas which make the Color Computer less desirable than 
even the Atari 400 or the VIC-20. Perhaps I'm too sensitive 
but, I couldn't help feeling "they" were laughing at MY 
computer! Did anyone else get that feeling? If so, realize 
this: Every computer mentioned so far in this book was 
discontinued long before the Color Computer. Remaining 
virtually unchanged in its ' first five years, our "toy", as it was 
often called, continued to flourish while the others died off 
one by one! 

Three major events, instrumental in paving the way for the 
Color Computer information explosion, occurred in the 
opening months of 1981. The Micro Works and 
Computerware shared the distinction of being the first 
folks to offer software for the Color Computer. The 
"CBUG" monitor program and the "80C" disassembler, 
both from The Micro Works' Andrew Phelps, were re- 
leased in January. Accompanied by documentation contain- 
ing information about the Basic ROM, these fine program- 
ming tools would, in the right hands, reveal even more 
information about how the Color Computer worked. 

With the arrival of Radio Shack's Direct Connect Modem 

I in February, a feeling of "community" began spreading 
among the isolated ColorComputerists. UsingRadio Shack's 
Videotex, the first communications package for the Color 
Computer, users started "meeting" on CompuServe or, 
more frequently, local area bulletin boards to share informa- 
tion and discoveries. 

Of less significance, but certainly of interest. Spectral 
Associates introduced a 16K upgrade ($75.00), an editor/ 
assembler, plus several other utilities and one of the first 
games: Space Invaders. They were also in the process of 
developing Magic Box, which would enable Model I & III 
tapes to be loaded directly into the Color Computer. Magic 
Box enabled many to easily port (transfer then re -write) 
BASIC games and utilities from the popular Models I & III 
to the CoCo. 

The Connection-80 BBS (Bullefin Board System) of 
Woodhaven, New York, which went on-line March 22nd, 
was like hundreds of other Model I boards providing infor- 
mation for the Model I & Model III... with one exception. 
The sysop (system operator), having just purchased a Color 
Computer, started putting things on the BBS about the Color 
Computer and at 300 baud, news spread quickly about Bob 
Rosen's BBS. 

One of the main topics of BBS "conversation" at this time 
was an article in BYTE Magazine's March issue entitled: 
"What's Inside Radio Shack's Color Computer?". Au- 
thored by Tim Ahrens, Jack Brown, and Hunter Scales, 

the article contained the most comprehensive information 
ever assembled, including an in-depth look at the 6809E 
architecture, the job-description of all the major chips, the 

expansion port pin-out, the famous POKE 65495,0 speed 
poke, plus "... a tricky way to get 32K bytes of memory"! 
Although occasional Color Computer "tid-bits" were printed 
in various computer publications, they were usually in the 
form of reviews with no more information than found in the 
"Getting Started With Color Basic" manual. 

If, in those early days, you looked for information in Wayne 
Green's 80 Microcomputing, you missed out on lots of 
material appearing regularly in a publication called 68 Mi- 
cro Journal. 68 Micro carried the first information on the 
MC6883 SAM chip (Nov '80), the first Color Computer 
software ads and a tip on disabling the ROM-Pak auto-start 
(Jan '81), Mickey Ferguson's letter mentioning plans for 
starting Colorware (Jan '81), talk of an expansion interface 
from F&D Associates (Mar '81), and a letter from Tallgrass 
Technologies about their proposed disk system (Apr '81). 
The April issue also premiered the first dedicated Color 
Computer column, Bob Nay's "TRS80CC". 

Only in retrospect can Don William's 68 Micro Journal 

be truly appreciated. With a reader base made up of Mo- 
torola 6800 users, they, were among the first to realize the 
true potential of the 6809E powered Color Computer. 
Names like Star-Kits, The Micro Works, Computerware, 
Mark Data, Cer-Comp, Frank Hogg and others were in 
the pages of 68 Micro long before there was ever a Color 
Computer. With its support of the Motorola 68xx series 68 
Micro attracted some early seekers, most, however, gravi- 
tated toward 80 Microcomputing, others to 80 U.S., with 
still others trying BYTE. As more and more interest grew, it 
was inevitable that somebody, somewhere would start a 
publication exclusively for the TRS-80 Color Computer. 

Color Computer News (CCN) was the first dedicated 
Color Computer publication to hit news stands. Edited by 
Bill Sias and published by REMarkable Software of 
Muskegon, Illinois, CCN premiered with its May/Jun issue, 
a 48 page beauty, filled with program listings, reviews, 
letters from other users, and articles! Don Inman, Ron 
Krebs, Wayne Day, Tom Mix, Ken Kalish, Jorge Mir, 
Gary & Susan Davis, Tony DiStefano, D.S. Lewandowski, 
and Andrew Phelps were just some of the "new" users 
(weren't we all back then) whose names appeared within the 
first few issues. 

Another feature of CCN was all those lovely ads! Did I say 
ads?? As much as we may sometimes say we hate commer- 
cials, during the opening months of 198 1 many users poured 
through various computer magazines searching, not only for 
articles, but for that occasional ad which may have men- 
tioned the Color Computer. Lets face it, ads ARE an infor- 
mation source, especially when new software releases were 
few and far between. Although there were only a handful of 
companies supporting the Color Computer in its first year, 
there was a surprisingly large amount of great software and 
hardware that was available and/or under development. 

Tandy's Little Wonder 


The Micro Works had its CBUG, 80C disassembler, and 
16K or 32K upgrades. Editor/assemblers and "space in- 
vader" games were both available from Computerware and 
Spectral Associates. Eigen Systems was putting BASIC 
programs in ROM-Paks. The WOLFBUG monitor from 
Mike Wolf accessed 64K of RAM. F&D Associates re- 
leased a ROM/EPROM board and a Proto Board while 
announcing plans for an Expansion Interface. Both 
Tallgrass and Atomtronics were developing disk sys- 
tems, and Steve Odneal's Color Computer FLEX con- 
version was reportedly just about completed. Microsoft's 
Bill Gates (the daddy of Color Basic and Extended Color 
Basic) was interviewed in the May/June issue of 80 U.S. and 
said there would be a book dealing with the overall structure 
of both ROMs in the fiiture. 

As the Color Computer's first year came to a close in June, 
third party support was starting to gather momentum but, if 
Fort Worth didn't step up support, the TRS-80 Color Com- 
puter may die from parental neglect 

THE SECOND YEAR (Jul '80 - Jun '82) 

Following its 1980 debut, the CoCo bumped along with 
virtually no Radio Shack support. The next 12 months, 
however, would witness the biggest outpouring of Color 
Computer support to date. This period produced a flood of 
upgrades, modifications, hardware, software, and most im- 
portant of all, information. 

In July of 1981, the Color Computer's first anniversary 
roared in like a lion. Many users celebrated by upgrading to 
Extended Basic, buying various new peripherals, and/or 
signing up with CompuServe. A word of sympathy here for 
anyone who ordered Nelson's word processor advertised 
this month. By January of 1982, the software was still 
nothing more than an ad on the pages of a few magazines. This 
is often referred to as "vaporware"- lots of "hot air" (ads 
and other publicity), but no actual product. 

Another ad appearing that July was for the Exatron disk 
system. "32K PLUS DISKS $298.00", read the ad. One 
could call the listed toll-free number and be placed on a list. 
After about a month and a half the systems were finally 
delivered. Soon after most were ready for a return trip back 
to Exatron' s Sunnyvale plant. The amount of generated RFI 
(Radio Frequency Interference) made the screen unread- 
able. This was in the early computer days, before the FCC 
(Federal Communications Commission) stepped in to regu- 
late the amount of interference a computer system could 
generate. Many small computers had little or no shielding! 
This was especially hard on apartment dwellers, as just 
turning a system on could interfere with a neighbor's TV and 
radio reception. Model I users would remember this well! 

Steve Odneal, at about this same time, was having a little bit 
better luck. With a home -built disk system hooked up to his 
32K machine and 8K of RAM on the disk controller board. 

Steve completed the first ever conversion of the FLEX 
operating system for the Color Computer. 

While Mark Data was rushing to convert their Model I 
adventure games to run on the Color Computer, 1MB (Illus- 
trated Memory Banks) released its first offering. Al- 
though written in Basic, Meteor Storm was the first soft- 
ware to take advantage of the CoCo's graphics capabilities. 
Thanks to Fred Scerbo, who authored Meteor Storm! July 
also witnessed the introduction of the first educational 
software from Micro-Learningware, and Strawberry 
Software, plus the first detailed instructions on performing 
the 32K "piggyback" upgrade. 

By the time CCN's Jul/ Aug issue arrived on your doorstep, 
two more Color Computer publications had sprung to life. 
The first ever cassette based Color Computer magazine was 
Dave Lagerquist's Chromasette Magazine. Instant soft- 
ware on a monthly basis for a mere $3.50 an issue was quite 
a deal! The "magazine's" first issue contained 5 Basic pro- 
grams and a very moving "cover". Very impressive!! In 
addition, all tapes were accompanied by a 5 or 6 page news 
letter explaining the programs. The news letter also featured 
tips, the latest rumors (Radio Shack disks soon?), and some 
of the editor's own "colorful" insights, which brings us to the 
second publication inaugurated in July. 

Whoever wrote the words, "From small acorns, large oak 
trees do grow" was, undoubtedly, referring to Lonnie Falk 
and The Rainbow. The Rainbow's first issue was all of two 
pages in length (both sides, of course) and you could tell 
immediately by the typeset (LP VII), that no expense was 
spared in putting together this latest collection of Color 
Computer information. The debut issue was photocopied at 
the corner drug store and after the first 25 copies sold out 
($ 1 .00 each), another trip to the drugstore was needed for an 
additional 10 copies. Containing the usual assortment of 
Color Computer articles, comments, tips, and program 
listings, the Rainbow became "legitimate" by the third issue 
with its first ads from The Micro Works and Jarb Software. 

Although initially set up for the Model I & III, by July, Bob 
Rosen's BBS was crawling with Color Computer informa- 
tion left by Wayne Day, Syd Kahn, "Barefoot" John 
Griffen, Cal Rasmusen, Kent Meyers, Lee Blitch, and 

many other "gurus" including Jorge Mir. Radio Shack's 
cassette based Videotex, because it was the first (and only) 
terminal program for the Color Computer at this time, was 
used exclusively by anyone calling Bob's BBS with a Color 
Computer. Videotex, a very limited piece of.... software, 
stored incoming information in a "buffer" but, downloading 
(transferring files/programs from the BBS to the calling 
computer), saving to tape, or printing out the buffer was not 
supported. When off-line, the only thing you could do with 
the buffer was look at it and, to make matters even worse, the 
only way to exit Videotex and return to BASIC was to shut off 
the machine. Thanks to the efforts of Jorge Mir, informa- 


Tandy's Little Wonder 

tion started showing up on the BBS about a Videotex modi- 
fication allowing an exit to BASIC by pressing the reset 
button, thereby preserving the text buffer. Download capa- 
bility was not too far away. 

The SDS80C from The Micro Works was the Color 
Computer's first editor/assembler. Although marketed in 
August '82, it had been a reality since June. It should be 
mentioned that Cer-Comp of Las Vegas, in a letter dated 
June 1, 1982, stated the availability of their editor/assem- 
bler which may make it actually "the first". The Micro 
Works, however, did get theirs to market first. Other notable 
releases in August included Mark Data's first two adven- 
ture games Calixto Island and Black Sanctum, Tallgrass 
Technologies' disk system and 64K RAM adapter board, 
and THE FACTS, a Color Computer technical manual from 
Spectral Associates. 

Barry Thompson, Tandy's Product Line Manager, in his 
column for Radio Shack's TRS-80 Microcomputer News, 
replied to Mark Grangers "PCLEAR 0" inquiry with this 
son read The Rainbow' s second issue, he not only would have 
found out about the PCLEAR trick but, he would have heard 
from a "very high placed source" that a Radio Shack disk 
system would be out within 2 months along with a 32K 
upgrade. Hadn't we heard those stories before? 

September is a time to return back to school. A time for 
learning, and learn we did. We learned from Radio Shack that 
the much rumored 32K upgrade was finally a reality. Al- 
though not mentioned, the upgrade included both the new E- 
board and 1.1 Basic ROM. One discovered that the first 
Color Computer word processor, C.C. Writer, was avail- 
able from Transformation Technologies. We were taught 
by C.J. Roslund that the PCLEAR "bug" could be fixed with 
a simple "reverse reference", and our homework assignment 
was to read Clay Abrams' documentation for another Color 
Computer first, his RTT Y/C W communications software ! 

The Sep/Oct issue of CCN debuted a column which quickly 
became one of the most popular: Comment Corner. Writ- 
ten by Andrew Phelps, author of The Micro Works' CBUG, 
80C Disassembler, and SDS80C, each column took an in- 
depth look at one of the Color Basic ROM routines. 

A first this month (September) from Computerware was 
the Color Computer's first alternate language: PASCAL. 
Computerware also started marketing Magicube (aRubick's 
Cube game), and Color Data Organizer. Steve Odneal's 
FLEX had, by this time, been converted to operate on the 
newly released Exatron system and, it worked like a "champ " : . 
According to Steve, the Exatron expansion board was the 
key, as it allowed the ROMs to be turned off and RAM turned 
on. Steve, while converting FLEX for the Radio Shack disk 
system, doubted the system would be capable of switching 

ROM to RAM. Steve would surely have gotten an "F" for his 
speculation that the Exatron disk system would be the 
"standard" disk system for the Color Computer, possibly 
surpassing even Radio Shack's. 

The month for trick or treating, October, saw the first details 
about the Radio Shack disk system, the debut of Bob Nay's 
Color Computer Users Notes in 68 Micro, plus the 
release of Aardvark-80's first 7 games. Another October 
treat was Dennis Kitsz's article detailing a modification that 
would deliver "true" lower-case instead of those unsightly 
inverse characters. This was the first lower-case board for 
the Color Computer, and was also available in kit form from 
MSB Electronics. Marketing began on Soft Sector 
Marketing's Master Control, the first single key entry 
utility. If you ordered immediately you were told "...some 
problems have cropped up and we'll be a few weeks late in 
delivering it...". Not again!!! Jorge Mir wrote an article 
describing how Videotex could be modified to return to 
Basic upon reset, thereby giving the Color Computer its first 
BBS download capability (the buffer content could be saved 
to tape). 

Although there were a few bulletin boards which supported 
the Color Computer, The Ark appears to be the first that 
actually ran on a Color Computer. "Barefoot" John Griffen, 
the sysop, operated the BBS from his houseboat in Portland, 
Oregon. Callers included Steve Den Beste, Shawn Jipp, 
Bob Rosen, and Ed March. 

Mike Wolf started marketing his Color Computer disk 
controller around this time (October). Unless one had 
either inquired or ordered his WOLFBUG monitor, chances 
are one didn't hear about it because the controller was 
marketed only through direct mail. With a price tag of 
around $350.00, the unit included an 80 column card, real 
time clock, and parallel printer port. In a phone interview, 
Mike said that a Michigan Computer Club was responsible 
for the sale of about 10 pieces. 

Thename "TRS-80" stands for Tandy Radio Shackandthe 80 
was a result of the Z-80 cpu in Tandy's first computer, the 
Model I. Because the CoCo uses a 6809 cpu, maybe it 
should have been called either a TRS-68 or a TRS-09 Color 
Computer, but what's in a name? Some nicknamed it the 
TRS-80CC, other the TRS-80C, still others the 80C. It was 
Dave Lagerquist who first used the name COCO in 
October's Chromasette Magazine. This innocent enough 
action set off a "name calling" debate lasting for several 
months throughout the ever growing "CoCo" community. 

Some things in the November winds included a tip to reduce 
internal heat produced by the 32K "piggyback" upgrades by 
painting the inside of the CoCo's top cover flat black, a 
rumor that Radio Shack was using half-good 64K chips in its 
32K upgrade, and an interesting article about CoCos being 
used to control Mr. Walt Bolden's solar heated home in 

Tandy's Little Wonder 

page 9 

Washington state. The computers were set up by Home 
Computer Systems, Inc., of Seattle. November also brought 
the first review of the Exatron disk system, the Program- 
mers Institute's tape magazine, TRC, but still no Super 
"Color" Writer. 

Nelson Software may have been dragging its feet, but not 
Cognitec. Within a couple of months of its November 
release. Telewriter was the talk of the CoCo community. 
Telewriter was the first "world-class" CoCo word processor. 
To this day. Telewriter is probably the most used CoCo 
word processor- nearly every Color Computer owner has 
used Telewriter in one of it's variations. 

after his BBS) in January and his first advertised CoCo 
product was Colorcom/E. Although Eigen ran his own sepa- 
rate ads, Bob's BBS probably accounted for a majority of 
initial sales. With every BBS sign-on being accompanied by 
a little "commercial", word spread very quickly, as the 
popularity of both Colorcom/E and the BBS grew rapidly. 
Truly a marriage made in computer heaven! 

1982 marked the start of CCN being published monthly. It 
also witnessed the debut of DSL's ML Rabbit, Sugar 
Software's Silly Syntax, Martin Consulting's Smart 
Term, Moses Engineering's Light Pen, Tom Mix's Moon 
Lander, and Frank Hogg's CCFORTH. 

Although it was possible to do primitive Videotex down- 
loading, Colorcom/E from Eigen Systems was light years 
ahead. It supported on-line/off-line scrolling, cassette file 
transfer, automatic or manual data capturing, off-line print- 
outs, and selectable RS-232 options. When Mark 
Davidsaver's Colorcom/E was ready for shipping, he mailed 
flyers to those who had responded to his "put your Basic 
program on a ROM" ad (June '81). Bob Rosen, upon receiv- 
ing his flyer, immediately phoned Mark. Colorcom/E be- 
came the first major software sold by Bob's Connection-80 
BBS. The rest, as they say, is history.... for both Bob and 

December saw not only the release of Computerware's 
Pac Attack (the first of many PAC-MAN clones) but a 
review of the Tallgrass Technologies disk system. This was 
probably the only disk system ever which would run in 4K! 

As 1981 drew to a close, reviews and comparisons were 
being made between the new Radio Shack disk system and 
the Exatron system. The consensus of opinion seemed to be 
that Exatron's single density format was its biggest draw- 
back, as it stored less information on a single diskette than 
the Tandy double density format. 

With third-party support growing dramatically, and even 
Radio Shack waking up, the CoCo's fiiture seemed secure 
but, into each life, a little rain must fall... 


Now, when most of us hear rumors, we usually consider the 
source. The more reliable the source, the more accurate the 
"information" is likely to be. Although it had been rumored 
for a while that Tandy was dropping the Color Computer, the 
rumor takes on special significance when, in January, it 
appears in Wayne Green's 80 Micro editorial. Since the 
beginning, critics had always pointed to the CoCo keyboard 
and snickered. A Dennis Kitsz article put a stop to all that by 
replacing the "chicklet" keyboard with a Model I keyboard 
(what would Dennis do next?). 

Bob Rosen started his company, Connection-80 (named 

In February, resumes were being accepted for the sysop of 
a Color SIG (Special Interest Group) which would soon be 
starting up on CompuServe, while in New England the 
CoCo was being used at the University of Vermont. Other 
events taking place at this time include the disk version of 
Telewriter undergoing final testing, Steve Blyn (soon to 
start Computer Island) marketing his first educational 
software, and violently negative reactions to Wayne Green's 
editorial started surfacing. Wayne sure didn't make too 
many friends that month! 

CCN's February issue was probably the best issue of any 
Color Computer magazine ever published. The issue was 
special for several reasons. If you were looking for a method 
of transferring your tape files to disk there was TPTDSK 
from Jack L. Aker, Tony DiStefano's article on running 
machine language programs from disk, and C.J. Roslund's 
article on disabling the BREAK key. What really marked this 
issue worth its weight in gold, however, was the article 
appearing on page 23 . . . 32K RAM FOR FREE! ! ! , by Frank 
Hogg (see FHL story for more on this). 

After Radio Shack's 32K upgrade became available, rumor 
had it that the "32K" chips used were, in fact, half-bad 64K 
chips. Frank Hogg's article detailed the steps required to 
enable your Radio Shack 32K CoCo (not "piggyback" 32K) 
to go into the "all RAM" mode, thereby giving the CoCo an 
effective 64K of RAM. Frank speculated (correctly) that, 
although very early 32K Radio Shack upgrades may have 
contained the half-bad 64K chips, most 32K upgraded CoCos 
contained prime 64K chips. Radio Shack's 32K upgrade also 
included the E-board and 1 . 1 Basic ROM. Although Frank 
Hogg didn't perform (or even make available) the first 64K 
upgrade, his article did bring to the CoCo community the 
information required to double the computer's effective 
memory and, in so doing, created a base for his FLEX 
operating system. 

In March, Kraft's new joystick (available within 2 months), 
Type-N-Talk from VOTRAX, and George Associates' Z- 
80 based CP/M interface were three new CoCo products 
previewed at the West Coast Computer Fair in 
San Francisco. Data-Comp debuted their FLEX operating 

page 10 

Tandy's Little Wonder 

system by marketing Steve Odneal's conversion which, at 
the time, utihzed the Exatron disk system. In an attempt to 
pacify software reviewers who had been waiting for the long 
overdue Super Color Writer, Nelson shipped their Super 
Color Terminal. Magazine articles at this time include 
Shawn McClenahan's detailed instruction on various 64K 
upgrades, a non-Kitsz hardware project for those of us who 
were tired of constantly switching the modem and printer 
cables from the back of the CoCo, and Frank Hogg's article 
on moving ROM to RAM in your "new" 64K CoCo. Perhaps 
in light of February's information flood, both CoCo publica- 
tions seemed to have had a lack-luster March issue. If I hear 
about the double-speed poke one more time, I'm going to 

With 2 FLEX operating systems available for the CoCo, 
Microware started looking into the possibility of porting 
its OS-9 operating system. Meanwhile, Dale Puckett's 
article "FLEX Comes To The Color Computer" along with 
the first installation of Frank Hogg's column "64K Komer" 
appeared in the April issue of CCN, marking their increased 
FLEX coverage. Clay Abrams' article, "Amateur Radio and 
the TRS-80 Color Computer", dealt with the reception of 
SSTV pictures. Wonderful information for ham operators, 
but it seemed like all the useful utility listings that had come 
to be expected from CCN were starting to disappear. 

The Rainbow, which by April had grown to 52 pages, 
contained the first part of Dennis Lewandowski's column 
called "The Assembly Comer", plus Rainbow On Tape. 
Telewriter's disk version was being marketed by this time 
along with several other new CoCo products, such as HUM- 
BUG, a machine language monitor program from Star-Kits, 
various software from Prickly-Pear Software, Auto Run 
from Sugar Software, The Solution (the first hi-res screen 
utility) from Snake Mountain Software, and NANOS Sys- 
tems reference card. 

Wayne Green must have freaked out when, in May, Tandy 
opened a 100,000 square foot plant in Fort Worth specifi- 
cally to build Color Computers. Several New Jersey schools 
also started using the machine at this time. Seems like 
everywhere Wayne Green looks, there are CoCos (dicing of 
neglect, no doubt)! 

CCN celebrated its first year anniversary with apologies 
from Bill Sias about the "double" issue but, said it was needed 
to get back on schedule. While still a source of valuable 
information, the number of good articles and programs 
seemed to be declining. 

Some CoCo firsts in May included an EPROM burner from 
Computer Accessories, Disk Doctor from Superior 
Graphics, Spell 'N Fix from Star-Kits, and the first BA- 
SIC Compiler from Aardvark. Spectrum Projects de- 
buted as Bob Rosen dropped the name Connection-80. And 
finally, a review of Super Color Writer from Nelson. 

The first national CoCo Users Group was inaugurated in 
June when CompuServe started it's Color Computer SIG 
with a membership of 52 and Wayne Day as sysop. 80 
Micro ran an interesting biography about Bob Rosen and 
his Connection-80 BBS. Thanks for the plug. Bob! Newly 
introduced CoCo support included Micro Technical Prod- 
ucts' LCA-47 lowercase kit (the first kit featuring switch 
selectable inverse screen), and the Rainbow Seal of Certi- 
fication. Started by The Rainbow magazine, certification 
insures that the product does, in fact, exist. John Walco's 3 
part article on picking winning NFL teams with the CoCo 
began but, unfortunately, there would be no winners that year 
because the NFL went on strike. 

Was it my imagination, or were both Color Computer 
magazines getting stale? Due, perhaps, to the sudden abun- 
dance of CoCo information in the second year, both ap- 
peared to be getting a bit thin. 

THE THIRD YEAR (Jul '82 - Jun '83) 

Despite rumors of its demise, the COCO celebrated its third 
birthday in fine health. With year 1 shrouded in mystery, and 
year 2 producing tons of information and software, what 
could we expect from year three?.. ARCADE GAMES and 

First shown at the West Coast Computer Fair in February, 
George Associates' CoCo CP/M expansion unit hit the 

market in July. Although it looked impressive, who was 
going to drop $1200.00 to upgrade a CoCo? Did anyone out 
there buy one of these?? 

In July, in "the best get better" department. The Micro 
Works unveiled its disk based editor/assembler, MACRO- 
80C. Tony DiStefano's first "Color CUnic" column in 68 
Micro explained why some CoCos would not accept the 
double-speed poke, and Donald J. Sommer of Seattle, 
Washington, detailed the steps required to upgrade a pre E- 
board CoCo to 64K. CCN continued putting more emphasis 
on FLEX, OS-9, and other CoCo operating systems but, 
features Darrel Wright's utility to convert Telewriter text 
files from binary to ASCII and vice-versa, and some pictures 
taken at a Cincinnati TRS-80 users meeting. Plans were 
disclosed to offer CCN on Tape and winners of the first 
CCN programming contest were announced. They were: J. 
Ventling for the George C. Scott portrait, Garry Howard for 
the William Tell Overture, and Regena's Cookie File pro- 
gram. The Rainbow'sfirst anniversary issue wasabeauty! ! 
Featuring its first full-color cover and typeset copy through- 
out, it's hard to believe that it started out in a drugstore a year 
ago. Rumors circulate that the 4K CoCo will be discontin- 
ued and a 64K version will be introduced in the near future. 

The first CoCo hardware to reach the market in August 
included F&D Associates' EPROM board. Color Port 
from Maple Leaf Systems, Botek Instruments' serial to 
parallel printer interface, plus Shawn McClenahan's ar- 

Tandy's Little Wonder 

page 11 

tide describing the installation of a Mod III keyboard (with 
numeric keypad) in the CoCo. 80 MICRO ran its first annual 
Reader's Poll to find out the most popular software for 
Radio Shack machines. 

With Frank Hogg writing the editorial in the August issue 
of CCN, things were really getting out of hand with all the 
FLEX material. There was the editorial, plus several full- 
page ads for his products, and of course his 64K Komer. It 
seemed like CCN had turned into the Frank Hogg magazine. 
Although a bit less technically oriented. The Rainbow con- 
tinued growing and soon surpassed CCN in size. 

With the addition of his second BBS, Bob Rosen's Spec- 
trum Projects was growing too. His ads now took up three 
full pages, and in August, included Eigen's one key entry 
utility, BASIC Aid. Both BASIC Aid and another new single 
key entry utility. Platinum Software's Platinum 
Worksaver, offered much more than the first such utility, 
SSM's Master Control. Med System started marketing its 

The "eyes" have it! ! In September Tony DiStefano's Color 
Clinic column featured the eye-saving hardware mod which 
enabled the CoCo to display green characters on a black 
screen. Whenever I sat at my machine for hours on end 
(usually every night), I thanked "Tony D.". Motorola re- 
leased a "souped-up" MC6883 SAM which supposedly al- 
lowed double-speed operation in the all RAM (64K) mode, 
but it was never marketed. New arrivals for the CoCo 
included Star-Kits' STAR-DOS, The Toolkit from Arzin, 
joysticks from Endicott, Spectrum Projects' "gloom" 
stick. Game Writer from Washington Computer Ser- 
vices (a $129.00 program that helped write "super-action 
video games"), and software from a new company called 

September's CCN issue (no date on the cover) featured a 
look at the CoCo's INTERPRET routine in Andy Phelps' 
Comment Comer column, CCXREF from Mike Donahue, a 
fine debugging utility used to locate variables in BASIC 
programs, and the first review of Eigen's The Stripper, a 
utility which removed spaces and comments, and "packs" 
program hues. The Rainbow's 106 page September issue 
made it the BIGGEST CoCo magazine in publication. Be- 
sides being their first official "theme" issue (education), and 
containing a readers survey, the Rainbow's cover mentions 
support for the TDP 100 computer... 

The TDP was Tandy's first venture at marketing outside 
Radio Shack stores. The TDP 100, which was really a CoCo 
in a white case, was marketed by RCA distributors and would 
later be found to contain the "F" (or "285") board, which 
would soon start showing up in the CoCo. Speculation was 
that the TDP venture would be successful (it wasn't!). 

In October, 68 Micro went on line with its BBS, and Andy 
Phelps' last Comment Corner appeared in CCN. The 
Rainbow, meanwhile, started Charlie's Machine, a col- 
umn written by Charles J. Roslund, author of War Kings. 

Dragon LTD., a British company, started making the Dragon, 
a CoCo clone. It used a similar BASIC and software but 
featured some major hardware differences- like full-travel 
keyboard, parallel printer port, and composite monitor out- 
put. An American version would be available sometime in 

Messages on CompuServe's Color SIG rumored that a 
new CoCo magazine would debut in March of 1983. MSB, 
the folks who marketed the Kitsz lowerkit, folded. Radio 
Shackannounced that they would market a 64K upgrade and 
a Multi-Pak Interface in early 1983. Basic Technology 
marketed the first CoCo expansion interface plus a real- 
time clock/calendar. 

Just in time for Christmas, November releases included 
Color LOGO and a four color graphics printer from 
Radio Shack, Frank Hogg's five slot expansion unit 
called The Solution, and Telewriter/64. Other marketings 
were Dunkey Munkey from IntelUtronics, and Monkey 
Kong by Ken Kalish of Med Systems Software. Although 
these are the first two "monkey" programs (actually "Donkey 
Kong" arcade game clones), the best is yet to come! 

A premature ad for the Sampo Color Computer ran in 
November' s BYTE magazine, but this CoCo clone never saw 
the light of day in the U.S. The machine was supposedly sold 
in Korea the next year. A reasonable assumption would be 
that the manufacturer couldn't get around U.S. copyright 
laws (the ROMs were probably near duplicates of the CoCo ' s), 
which were not legally protected in Korea and most other 
Asian countries. 

With various disk systems available for the CoCo, the poor 
timing award went to JPC Products Co. for their high- 
speed cassette system. One can only wonder how many 
systems were sold at the $129.95 price. 

Lonnie Falk announced plans for a big CoCo show for the 
Spring of 1983 in Chicago. It will be called RainbowFest! 
Lonnie also hinted at an "electronic" Rainbow in conjunction 
with Bob Rosen's BBS. November also gave us the first look 
inside the new TDP- 100 computer, and the first review of 
Eigen's disk ColorCom/E. 

When CCN first came out, it contained a lot of basic CoCo 
information, but with the magazine stalled at the 90-100 
page size and Bill Sias devoting more ad and column space 
to FLEX, OS-9, GIMIX, and ham radio operations, much of 
the basic information was being squeezed out. The opening 
item in the December issue was a tour of the GIMIX plant! 

page 12 

Tandy's Little Wonder 

Rainbow announced support for the Dragon/32 in Decem- 
ber, its first perfect bound issue (square back with glued in 
pages, just hke a paperback book). Tom Mix's king of the 
Donkey Kong clones, Donliey King, was released just in 
time for Christmas. This is one of the best game ever done 
for the CoCo. Thanks Tom! ! ! ! 

The February rumors were obviously true, because in March 
the third CoCo magazine hit the news stands. Edited by 
Kerry Leichtman, The Color Computer Magazine 
(TCCM for short) premiered with articles from Jalie Com- 
mander, Bob Rosen, William Barden, Jr., and Dennis 


1982 closed out with a tip of the hat to the very inventive 
folks in Natick, Massachusetts for coming up with a very 

imaginative idea DEBUG. The concept worked like this: 

You sent these folks a program you wrote that may have bugs. 
If the program is interesting enough, they send your program 
to "people who like to stomp on other people's bugs". The 
understanding was that the program is sold (by them) if 
debugged, and everybody shares in the profits! The ad asked 
for $5.00 to accompany your "bugged" program, or $9.00 for 
a cassette containing 20 or so "bugged" programs from other 
people, or $12.00 for both. The idea of "buying" someone 
elses problems was (and still is!) a bit bizarre, however, and 
the ads soon disappeared. 

In January Jake Commander (CCM) predicted the arrival of 
the British made Dragon computer early in 1983. CCN 
started the year with a new cosmetic look including a new 
cover ("The Color Computer Magazine for 6809 users") and 
newspaper quality pages. 

Cosmetic changes also appeared in the Rainbow's January 
"Adventure" issue with the first Fred Crawford cover 
artwork! Fred brought a Norman Rockwell feel to the pages 
of The Rainbow, and many looked forward to Fred's covers. 
This issue probably had the first centerfold ever in a com- 
puter magazine. 

Other January events included Micronix Systems market- 
ing the first keyboard for the CoCo, Dennis Lewandowski 
writing the Rainbow Check, and dates confirmed for the 
first RainbowFest. It was held in Chicago, April 22-24th. 
Peter Stark, one of the pioneer CoCo supporters, started 
including little "tips" in his ads. Peter was a real innovator 
both in software and advertising. 

March's "nuclear" issue of Rainbow featured the first Rain- 
bow Scoreboard and an ad for Elite Software's ZAKSUND 
(the first ZAXXON clone). The Mark Data replacement 
keyboard was also reviewed. 

In late April of 1983 users from across the United States 
and Canada (not to mention Great Britain, Germany, Hawaii, 
and the Yukon) descended upon Chicago to take part in the 
first ever CoCo convention, RainbowFest! Estimated at- 
tendance for this 3 day bash was around 10,000. On the sales 
floor, J&M unveiled its JFD disk controller, while semi- 
nars were held by Don Inman, Fred Scerbo, Tom Nelson, 
Steve Bjork, and Charles Roslund, to name a few. 

TCCM's April showers included the cross reference index 
disassembly of 1. 1 ROM, the first ad for Computerware's 
64K Screen Expander, word that Bob Rosen was then 
operating 3 bulletin boards, Jake Commander's first install- 
ment of the most ambitious commenting of the BASIC ROM 
ever, and the appearance of Datasoft's first ZAXXON ads. 
May brought flowers and a cross reference index disassem- 
bly of the 1.0 EXTENDED BASIC ROM to TCCM, plus a 
name change for Med Systems to Screen Play. What's in a 
name anyway? 

The Comment Corner column returned to CCN in June, 
authored by Andrew Hubbell, and a list of differences for 
BASIC 1.2, EXTENDED BASIC 1 . 1 , and DISK BASIC 1.1. 
CoCo's third year ended with two new releases. First: the 
long awaited and much rumored "new" Color Computer, the 
Radio Shack MC-10. Second: another Color Computer 
magazine. HOT CoCo, a Wayne Green publication, de- 
buted without so much as a word of credit to Dave Lagerquist 
for coining the name "CoCo" for the Color Computer... oh 
well, we will remember! 

In February, 68 Micro eluded to the fact that they may be 
starting a CoCo publication to meet the explosion of "new" 
subscribers. Absent, for the first time since many issues of 
68 Micro, are The Micro Works ads. Was something 

Most of the other February news included reports of CoCo 
products on display at last fall's COMDEX show in Las 
Vegas. The products included AMDEK's new 3 inch disk 
drives, WICO's joysticks and trackball, and the long 
awaited ZAXXON from Datasoft (a licensed version of the 
arcade hit, not a clone!). 

THE FOURTH YEAR (Jul '83 - Jun '84) 

CCN definitely seemed to be nearing its end. In July there 
was a full-cover photo of the Dragon/32 but nothing on the 
inside about the computer. Rainbow magazine, now sup- 
porting the MC-10 also, celebrated its second anniversary 
with a 308 page issue containing a two year index, a record 
with some BASIC programs, a look at the "new" MC- 10, and 
a review of April's RainbowFest. Marketing began for Un- 
Disk from Dr. Preble, Elite Calc from Elite Software, 
and PBJ's 80 Column Card. If 64K wasn't enough for your 
CoCo, you could always try Dennis Kitsz's 128K bubble 
memory upgrade which appeared in July's TCCM. 

Tandy's Little Wonder 

page 13 

A new CoCo magazine, 68 Color Micro Journal, was 
announced in August, which brought the number of dedi- 
cated magazines for the CoCo up to five. Just about all 
magazines carried articles on the MC-10. New product 
announcements in August included a new CoCo keyboard 
from HJL, the Multi-Pak Interface from Radio Shack, 
Piratector from Sugar Software, and Chromasette going 
to disk. Soft Sector Marketing stopped marketing CoCo 
software. Several hundred OS-9 users "got together" (mainly 
through BBS and E-mail systems) and formed the OS-9 
Users Group. Dale L. Puckett (author of Microware's 
Official Basic09 Tour Guide and KISSable OS-9 column 
for Rainbow) was elected president and Peter Dibble (wrote 
monthly OS-9 column for 68 Micro Journal) vice president. 
The stated purpose of the group was: "1) To stimulate and 
sustain interest in microcomputers in general and in OS-9 in 
particular. 2) To promote the cooperation and exchange of 
information between members. 3) To conduct programs and 
activities to promote fratemalism and to advance the general 
interest and knowledge of members." 

Always on the leading edge, Star-Kits started its "software 
amnesty" program. Anyone with pirated Star-Kits software 
could send in a registration fee and receive a valid copy. Who 
but Peter Stark would be bold enough to give software 
pirates a chance to cleanse their souls? Star-Kits also mar- 
keted the first MC-10 software, HUMBUG, a machine 
language monitor. 

If you needed a new computer to take back to school with you 
in September, you might try the newly released CoCo 2. 
Don't bother subscribing to CCN because, unknown to its 
subscribers, the September issue was the last. 

Reports circulated that The Color Computer Magazine 

wouldhold COLOR EXPO '83 in Pasadena, CA. November 
4-6. Not to be outdone. Rainbow would also hold more 
RainbowFests in the fiiture. 

New products released in September included Color Mi- 
cro Journals 32 page debut issue, Pooyan from Datasoft, 
a keyboard from Keytronics, Pro-Color Forms from 
Derringer Software, and the Dragon/64 from Tano Mi- 
crocomputer Products Corp. of New Orleans, Louisiana 
(the American distributor for the previously mentioned 
British CoCo clone). Nelson announced that Super Color 
Writer was the official word processor for the Dragon. 

In November, at Color EXPO '83, Marty Goodman de- 
buted his state of the art graphics program Graphicom. 
Other new releases were Elite Word from Elite Software, 
Super Screen from Mark Data, PASCAL from DEFT 
Software, the BASIC Unravelled books from Spectral 
Associates, and Computerware's first BASIC Compiler. 
Nelson Software changed its management and name- to 
Softlaw Corporation. Super Color Library programs 
became "VIP Library" programs. 

With Christmas only days away, TANO started including 8 
FREE programs with its Dragon/64 (home finance, word 
processing, and games). Things did not look good for the 
only CoCo clone. Reviews for the Dragon/32 and Dragon/ 
64 appeared in a couple of publications along with the 
announcement of Time Bandit from the Computer Shack, 
Magigraph from The Micro Works, and POKES, PEEKS 
& EXECS books from Microcom Software. 

In January, a Barcode Reader called OSCAR was adver- 
tised in several computer magazines for different machines, 
including the CoCo. Programs could be printed in maga- 
zines normal printing presses using barcodes... no need for 
expensive companion disk or tape subscriptions, just a one- 
time purchase of an Oscar by the user. And Oscar was 
independent- with a software change he was ready to connect 
to virtually any computer with an RS-232 port. This $ 1 78 ill- 
fated project ended up being liquidated for $54.00 or less 
(some can still be found today!). Wayne Technology mar- 
keted its CP/M for the CoCo (actually an add-on Z-80 CPU 
board), and Dynamic Electronics marketed the first ever 
128K upgrade. 

February marked the debut of Graphicom from Marty 
Goodman, and Elite-File from Elite Software, plus a 
name change for the Computer Shack to Michtron. A new 
newsletter. Dynamic Color News, was launched by Bill 
Chappie, owner of Dynamic Electronics. The first edition 
contained comments by the editor, a Q&A column, operat- 
ing hints, and several programming tutorials. The newsletter 
was printed on heavy white paper in an 8 l/2"x 11" format. In 
addition to printing the newsletter. Dynamic Electronics 
also offered soft and hard ware for the Color Computer. 

RainbowFest #3 was held in Long Beach, CA, February 17- 
19. Radio station KGON, it was reported, had its own 
bulletin board running on a CoCo. 

The highlight of the second RainbowFest (held in Fort 
Worth on October 1 4- 1 6) was a walking tour of Tandy ' s new 
CoCo Plant. The same month Radio Shack released the 
Walt Disney and Sesame Street educational software, 
Multi-Pak Interface, the Color Mouse, the Deluxe (Kraft) 
joystick, and the OS-9 operating system. Dennis Kitsz 
said "I'm gonna teach you a lesson" when he released his 
6809E Instructional Kit, which came complete with text 
and audio and program cassettes. 

The first East Coast RainbowFest was held March 30 - 
April 1 and featured the first CoCo Hard Disk from Soft- 
ware Support. In an attempt to clear its stock, TANO 
reduced the price of the Dragon/64 to $149.00. The last 
Dragon/64 ad in Rainbow appeared this month, and rumors 
started circulating that the computer was about to breath its 
last flame. The OS-9 Users Group found a medium to 
communicate with members and potential new members- 
the OS-9 Users Group President's Column in the Rain- 

page 14 

Tandy's Little Wonder 

bow. The debut article featured general information about 
the relatively new group. Membership wouldbe $25 per year 
and new users would receive one free disk from the library 
(additional disks were $3 for members). A condensed li- 
brary directory was also published. Disks would be sent on 
standard OS-9 5 1/4" or 8" floppies as well as CoCo 5 1/4" 
(single sided 35 track) format. 

Bob Rosen moved Spectrum Projects to San Jose, Cali- 
fornia, in May. Word was out about the future release of the 
C-Compiler from Radio Shack, and VIP CALC from 
Softlaw. New product releases came from Prickly-Pear 
Software with their Disk Trivia and the Tom Mix mile- 
stone. Worlds of Flight- the first real flight simulator 
for the CoCo. This was the last issue of Rainbow that the OS- 
9 Users Group President's Column appeared in. A short note 
asking for assistance with group activities and new members 
appeared. Dale Puckett would print highlights from the user 
group in his KISSable OS-9 column from then on. 

By the time the June 22-24 RainbowFest touched down in 
Chicago, Dragon/64 ads had vanished from all CoCo maga- 
zines as Dragon Data Ltd. (British parent company) went 
under receivership. It seemed that "...The Color Computer 
You've Been Waiting For" wasn't fairing as well as expected. 

THE FIFTH YEAR (Jul '84 - Jun '85) 

The CoCo turned 4 years old in July, at the same time Radio 
Shack's TRS-80 Microcomputer News published its last 
issue. The Rainbow celebrated its third anniversary with 
yet another innovative feature, a scratch 'n sniff adventure 
game. The issue also contained a complete index of articles 
and reviews which have appeared in the magazine since its 
beginning. Rumors appeared about a new Radio Shack 
CoCo keyboard, and the folding of Chromasette. A new 
product called Tele-Form was first marketed by CIGNA. 
The software enabled mail-merge with Telewriter. 

InAugust, TCCM wasthe subject of "going out of business" 
rumors. Bob Rosen put BBS #5 "on the air" in San Jose, and 
rumors circulated in England that Tandy was interested in 
the floundering Dragon Data Ltd. company. 

At the September RainbowFest, held in Princeton, NJ (28- 
30), Dennis Lewandowski debuted his 128K upgrade. 
Other first timers include NOMAD the robot from Frank 
Hogg, Graphicom II from Whitesmith, and a graphics 
program and digitizer from GRAFX. The rumored take- 
over by a Spanish company (EUROHARD) gave British 
Dragon users something to roar about. Dragon production 
was moved to Spain when the takeover was finalized in 
October. Soon after, TANO Microcomputer Products 
Corp. sold their remaining stock to California Digital. 
Included in the deal was a number of joysticks and software. 
The number of computers was undisclosed, but CD was still 
selling them in March of 1993 for only $39. At this time 

there were under 1000 left. Many had reportedly gone to 
South American companies and schools. The Dragon ended 
up having a long life after all! 

TCCM's rumored demise proved correct as the last issue 
appeared in October. This was the third CoCo magazine to 
fold within the past year (including Chromasette 's Disk 
Magazine). Dennis Kitsz also announced the start of Under 
Color (UCL for short), which hit newsstands in November. 

An auto-answer modem too expensive? Check out the No- 
vember issue of Rainbow and find out how to teach your 
Modem I to auto-answer. Bill & Sara Nolan sold Prickly- 
Pear Software to Mike & Joanne Chinitis. Rumors, 
rumors everywhere: Radio Shack has CoCos with true 
lowercase (using the new Motorola 6847-TI VDG chip) 
which won't be released until after the holidays. 

Better late than never, a 26 page Under Color magazine 
premiered in December with information about two "new" 
Korean manufactured (for Tandy) CoCo 2s featuring a 1.3 
BASIC ROM. Other new December arrivals included The 
Wizard from NEXUS which modified Telewriter's charac- 
ter set, Dennis Lewandowski's 128K upgrade, the 
Calindex appointment scheduler from Grantham Soft- 
ware , a video digitizer from The Micro Works, and 
NOVASOFT (a Tom Mix company) started marketing its 
CoCo goodies. 7000 people attend Britain's first 6809 
Colour Show for Dragon and Tandy CoCo users. 

1 985 started with abang and a whimper! The bang came from 
the debut of another CoCo milestone, CoCoMax from 
Colorware. Like Telewriter, nearly every CoCo user has 
seen or used this graphics program, which was patterned 
after MacPaint (for the Apple Macintosh). The whimper was 
provided by rumors that Color Micro Journal was about to 

The February RainbowFest in Irvine, California (15-17) 
attracted 8,000 visitors for a first-hand look at CoCoMax 
(250 sold). Product debuts included the P-51 Mustang 
Attack Flight Simulator from Tom Mix, the 68008 ex- 
pansion card from RGS Micro Electronics, and a 15 key 
numeric keypad from Moreton Bay. Tandy sold 16K 
CoCos for a mere $50, a drop in the proverbial bit bucket. 
Back to where it all started, CoCo information will start re- 
appearing in 68 Micro Journal as rumors of 68 Color 
Micro Journal's demise prove true. With this month's 
issue, CMJ joined Color Computer News, Chromasette, 
and The Color Computer Magazine as the fourth major 
CoCo publication to fold within the past 17 months. 

March brought word that the "new" CoCo would be an 
exclusive OS-9 machine (no BASIC ROM) and wouldbe in 
Radio Shack stores sometime between September '85 and 
March '86. Callers to any of Bob Rosen's 4 bulletin boards 
in Woodhaven, New York were greeted not by the usual high 

Tandy's Little Wonder 

page 15 

pitched carrier tone but by a "disconnected" message. Bob 
signed off the east coast boards. On March 30-3 1, London 
is the scene of the second 6809 Colour Show for Dragon 
and CoCo users. Looks like the Dragon lives on. R.G.S. 
Micro Electronics (Montreal, Canada), who had just de- 
buted their 68008 expansion, folded. 

April saw the release of two library offerings, the long 
awaited Complete Rainbow Guide to OS-9, authored by 
Dale Puckett and Peter Dibble (president and vice presi- 
dent of the OS-9 Users Group, respectively), plus, from 
our Canadian friends at Dragonfly Writing, a cassette 
magazine called DIGInews For CoCo. Spectral Associ- 
ates withdrew their support for the CoCo after four 
years of very good products and service. 

In May, voice recognition for the CoCo becomes a reality 
when Speech Systems started marketing its Electronic 
Audio Recognition System (EARS for short). Rainbow- 
Fest celebrated the third anniversary of CoCo shows with 
three fun-filled days & nights (17-19) in Chicago. Causing 
quite a stir was Steve Odneal's fully portable CoCo, 
complete with disk drive and monitor built in. Although only 
a prototype, Steve used the show to judge user interest. It 
may have made production had a good low cost screen been 
available. Unfortunately, the three inch LCD TV was just to 
small to be practical. 

In June, as the curtain descended on the CoCo's fourth year, 
so too does it fall on yet another Color Computer publica- 
tion. This time it's Dennis Kitsz's "Under Color" which 
folded after just seven months of publication. 

THE SIXTH YEAR (Jul '85 - Jun '86) 

Subscribers to Under Color magazine were informed in 
July that any unfullfiUed subscriptions would be taken up by 
Rainbow magazine, celebrating its fourth anniversary. 
Rainbow was now the only widely circulated printed publi- 
cation exclusively for the TRS-80 Color Computer, which 
itself turned five years old in July. Though somewhat over- 
shadowed by Rainbow, Dynamic Color News had become 
a small magazine by this time and started printing product 
reviews this month. While Rainbow had a circulation in the 
tens of thousands. Dynamic only had just over 200. 

In November, a little over four years after their debut on the 
CoCo scene, the absence of the Nelson/SoftlawA^IP (take 
your pick) ads were keenly felt. They were one of the first, 
but sadly not the last, large advertisers to start dropping 
CoCo support. This did not spell the end of availability of 
Softlaw/VIP products, however, as other vendors still adver- 
tised them. 

system used an SCSI interface made by L.R. Tech and 
required a MPI or Y cable. The J&M system was operated 
through the parallel port on their floppy disk controller, no 
external controller or MPI was needed. 

THE SEVENTH YEAR (Jul '86 - Jun '87) 
On July 30th, 1986 (6 years and 1 day after the debut of the 
original TRS-80 Color Computer) Tandy unveiled the 
long awaited and much rumored CoCo 3. The basic unit 
($219.95) came with 128K (upgradable to 512K) and a 
"Super Extended" BASIC. Also announced were the OS- 
9 Level II operating system (which allowed use of the 
expanded memory) and a new analog RGB monitor. 

Due to small attendance, August brings word of Rainbow- 
Fest West's possible demise. Chicago & Princeton shows, 
however, will not be affected. Dynamic Color News started 
a column on "Ham Radio & Computers". Dynamic Electron- 
ics and their magazine quickly became THE SOURCE for 
Color Computer HAM software. The HAM column became 
a regular feature after this. Could have had something to do 
with Bill Chappie getting his HAM hcense (W4GQC as of 
January 1993)... 

Rainbow's September issue carried the first in-depth look at 
the new CoCo 3 (the cover states coverage for Color 
Computer 1,2, and 3 for the first time). On power up, the 
68B09E gets the 2 byte address at &HFFFE, puts it into the 
program counter and starts executing code. In the case of the 
CoCo III, the address found at &HFFFE is &H8C1B. The 
GIME chip (Graphics Interrupt Memory Enhancer, a cus- 
tom job specifically for the CoCo 3) initializes to read the 
CoCo 3 ROM even if the system has the disk controller 
(Disk BASIC ROM) installed, so after entry at &H8C IB the 
CoCo 3 goes to its internal ROM at &HCOOO. Computer 
Plus sold the new CoCo 3 for $169 at the October 
(Princeton) RainbowFest, where they sold out within 

The first CoCo 3 only programs, two graphics demonstra- 
tion programs, were pubUshed in the October Rainbow. 

Also introduced this month was a new service- Rainbow on 
disk. The disk was a "flippy" with BASIC programs on one 
side and OS-9 on the other. It was predicted that OS-9 would 
play a leading role in the future of the CoCo 3, especially 
since Tandy announced that all new software development 
would be under OS-9 (with the exception of ROM pack 
games). Disto finally followed the lead of Owl-Ware and 
J&M by advertising a hard disk adapter for their Super 
Controller- coming soon! 

It seemed that 1986 would be the year of the hard drive, with 
Owl-Ware advertising a five megabyte hard drive system 
for $495 in November '85 and J&M Systems advertising a 
five megabyte system for $495 in December. The Owl 

page 16 Tandy's Little Wonder 

Yet another Color Computer magazine was advertised in the 
November issue of Rainbow! Spectrogram offered users 
columns on telecommunications, BASIC and Pascal pro- 
gramming, OS-9, and more. Bill Bernico was the most 
known contributor. 

In the coming months, it is almost like the introduction of 
the original CoCo! Owners of the new CoCo 3 were pouring 
over the remaining CoCo magazines looking for new prod- 
ucts and information that took advantage of the great new 
features. Except for a few offerings from Tandy (such as 
Decembers unveiling of DeskMate 3), the pickings were 
few and far between. 

Spectrum Projects became the first third party vendor to 
advertise software for the CoCo 3. First came C III Draw, 
a graphics program, in December, then Elite Word/80 in 
February- a word processor that used the 40 and 80 column 
screens and expanded memory. Like many programs to 
come, this one DID NOT work on previous CoCo models. 

Cer-Comp started advertising versions of their software 
for the CoCo 3 in January. These special versions are only 
interim versions though! Cer-Comp had software that took 
full advantage of the power in the new CoCo still in the 

In February, Rainbow reprinted an old article- the first (and 
only) time this was done. The article was a utility to transfer 
tape programs to disk. The reprint is due to the programs' 
popularity (it successfully transfers machine language as 
well as BASIC programs) and the popularity of Rainbow on 

June marked the arrival of the first CoCo 3 only graphics 
program: Computize's Color Max 3. Picture convertors to 
allow use of pictures in Atari ST (.ST, .NEO, and .TNY), 
Graphicom, and CoCo Max formats as well as several 
supporting utility programs are also offered. Cer-Comp 
started advertising their first CoCo 3 only products. A 
communications terminal, disk editor/assembler, and screen 
enhancing programs were described. A word processor, 
disassembler, and BASIC enhancer were promised, even by 
the time the ad was out! Speaking of BASIC enhancements. 
Art Flexser (Spectro Systems) introduced ADOS-3 for 
$34.95 this month. Although it was for the CoCo 3, it had a 
disable feature so that it could be burned into an EPROM and 
the disk controller could be used with a CoCo 1 or 2 also. 
Double speed disk I/O, command line editing, and support of 
35,40, or 80 track as well as double sided drives were some 
of the new features. 

A new "magazine" was introduced this month also. This 
newsletter was created by two seventh grade friends who had 
discovered the Color Computer just a few years before. The 
name of the newsletter/magazine was TRS-80 Computing, 
and the publishers were Joseph Ahern and David McNally . 
The first few would be delivered monthly, but the boys soon 
found that a bi-monthly schedule worked around their school 
work better. Good work guys, shows just what a couple 
imaginative teenagers and a computer can do! 

Disto finally started delivering the long promised hard 
drive interface in February of 1987. Since it fits inside the 
Super Controller, there is no need for a MPI, and it makes for 
a neat installation. Good thing... J&M stopped advertising 
their neat hard drive system a few months back... maybe 
Disto came around just in time! 

THE EIGHTH YEAR (Jul '87 - Jun '88) 

The new CoCo year started with the introduction of a much 
needed book: The Complete Rainbow Guide to OS-9 
Level II - VoL I: A Beginners Guide to Windows. As the 

title suggests, the main subject of this volume was the new 
windowing system of OS-9 Level II. Very little was men- 
tioned about the operating system in general, necessitating 
the need for the original Rainbow Guide to OS-9 also. 
Still, this book provided much needed information to the 
beginner and experiencedOS-9user alike. The "Vol. I" in the 
title led readers to believe that other volumes were forth 
coming. It is unknown whether more were planned, but there 
were no further volumes published or advertised. The book 
was advertised for August delivery. 

It seems everybody was out to capitalize on the outstanding 
graphics capability of the new CoCo. Even Owl-Ware got 
into the act with the introduction of DaVinci 3 in August. A 
unique feature was that no hi-resolution adapter was needed, 
fine control of the input device (joystick, mouse, X-pad, or 
touch pad) was accomplished via software. 

Diecom Products quickly followed Computize and Owl- 
Ware with a graphics program of its own in September- the 
Rat. This package came complete with a two-button digital 
mouse (not the Tandy analog mouse). Almost all functions 
were accessed through the mouse with pull-down menus. 
Iron Forest, a unique game which used a SEGA light gun, 
and several other CoCo 3 only games were also introduced. 

Not to be outdone in the graphics field, Colorware intro- 
duced an updated version of its popular CoCo Max pro- 
grams... CoCo Max III (naturally!) for the CoCo 3, which 
also debuted in the September issue of Rainbow. Rather than 
creating an entirely new hi-res adapter, Colorware supplied 
a modified Tandy hi-res adapter that did not require using the 
cassette port. Animation and color sequencing were special 
features of the new program. The November issue of Rain- 
bow featured a Colorware ad comparing CoCo Max III to 
Color Max 3. Interestingly, the ad was back to back with a 
Computize Color Max 3 ad! 

Cer-Comp released a terminal program, word processor, 
and BASIC compiler for the CoCo 3 only in September also. 
The word processor supported 512K by adding two RAM 
disks. Mail merge and even laser printers were supported! 
The ad was even edited and printed using Textpro IV and an 
Okidata laser printer. 

Tandy's Little Wonder 

page 17 

With desktop publishing so popular, it is no wonder that 
CoCo users would be very interested in publishing pro- 
grams. Rainbow started a very ambitious series which 
resulted in a complete desktop publishing program for 
the CoCo. Separate versions were available for the CoCo 1/ 
2 and CoCo 3. The programs were written by H. Allen 
Curtiss and did, indeed, prove to be very popular. Several 
upgrades would come later. 

Sundog Systems made their debut in the October issue of 
Rainbow with a half page ad. Their premier game was Kung- 
Fu Dude, the first full graphic martial arts game for the 
CoCo 1,2, and 3. Also advertised was Champion (previ- 
ously from Mark Data) and White Fire of Eternity (pre- 
viously from Saguaro). 

The 14th RainbowFest was held in Princeton, New Jer- 
sey 9-11 October. A new arrival to the CoCo market made 
their debut at this show with a hard disk adapter for the 
CoCo that allowed use of a standard PC type eight bit hard 
drive controller. Burke&Burke also had a version with a 
built-in real time clock. Tandy gave away 500 64K up- 
grade kits (the 16 RAM chip variety) and 4600 Plug n 
Power controllers. 16K CoCo 2s were sold for a mere 
$9.95 while 64K versions sold for only $29.95. CoCo 3s 
were on sale for $100 Friday night, but back up to $ 11 5 for 
Saturday and Sunday. 

October 1987 was just a memorable month for the CoCo! 
Not only were the previously mentioned software packages 
first available, but SD Enterprises started advertising 
Softlaw's VIP products for the CoCo 3! The original ver- 
sions would not all run on the new CoCo. 

The first commercial desktop publishing package, CoCo 
Newsroom, appeared in the November Spectrum Projects 

ad. Over 140K of code, 22 fonts, and 50 pictures were 
boasted. With new products being introduced, it is hard to 
believe that faithful Spectrum projects would not be in the 
CoCo market much longer... 

Howard Medical began selling hard drive systems using 
the Burke&Burke adapter shown at the last RainbowFest in 
December. They didn't say it directly in the ad, but the phrase 
"will also work with IBM & clones" sort of gave it away. 
Complete 20MB systems were sold for $699... a much 
better deal than the $999.95 5MB systems first sold in '84! 
The next month the first Burke&Burke ads appear, selling 
the hard disk adapter and software as individual components. 
This allowed individuals to get used PC hard drives and make 
their own systems at a substantial savings. Maybe the earlier 
systems just paved the way, and the Burke&Burke ad is 
correct... "1988 — The Year of the Hard Disk!". FHL also 
enticed us with an upcoming hard drive interface... claiming 
it to be the fastest. We'll see Frank, we'll see! 

In February of 1988, Microcom Software introduced a 

very powerful word processor for the CoCo 3, Word Power 
3 (amazing how original the titles for CoCo 3 only software 
could be!). This original version supported only 80 column 
displays. In addition to the usual word processing features 
Word Power sported mail merge and a 72K-450K text 
buffer (for 128K or 512K CoCos). A punctuation checker 
was added in April of 1988 (Word Power 3.1). FHL adver- 
tised their new hard drive interface. It was similar in some 
respects to the Owl- Ware and Disto interfaces in that it was 
really just an adapter between the CoCo and a controller. The 
secret to the speed was in the controller used- a high speed 
WD 1002-05. 

Cognitecs' Telewriter 64 had long been the most popular 
word processor for the CoCo, so the February introduction 
of Telewriter 128 for the CoCo 3 was no real surprise (a 
"coming soon" blurb was in the January ad). The new version 
was kept as close to the original (command wise) as possible 
while taking full advantage of the CoCo 3s' new power. Like 
Word Power, only the 80 column screen was supported. 
Fortunately, Telewriter 64 ran on a CoCo 3 with no problem, 
and an upgrade option was available, so those not yet having 
an 80 column monitor weren't totally left out. 

A real surprise this month was SD Enterprises' announce- 
ment of VIP Writer III. SD apparently had gained rights to 
the full source code of the VIP Library products! This was 
the first CoCo 3 word processor to support 32, 40, 64, and 
80 column screen widths. Other features included a built-in 
spell checker (no longer an extra-cost item!) and print 
spooling. Unfortunately, only a 48K text buffer was allowed, 
though the 48K print spooler buffer did allow editing one 
document while printing another. This would be rectified in 
a future release... 

February's Spectrum Projects ad was the last to grace the 
pages of a CoCo magazine. Orders were still filled for 
several months, and some advertising done by direct mail to 
repeat customers. Spectrum was sorely missed by many (the 
author included!). To end the month on an upbeat note. 
Dynamic Color News started a new series on OS-9 and 
Basic09. The 1 8th installment of the regular "HAM Radio & 
Computers" column was also printed. Good work. Bill! 

Lonnie Falk's editorial column in the March Rainbow was 
written to quell rumors that Tandy was considering dropping 
the CoCo 3. Many of the rumors started due to large price 
reductions of CoCo products. Mr. Falk sought to put the 
rumors to rest by stating that the CoCo was outselling all 
other Tandy computers combined, and the lower pricing was 
due to lower costs incurred in production. 

May 20-22 1988 brought forth the Chicago RainbowFest. 
Many vendors attended this annual gathering of CoCo enthu- 
siasts. Host for the show was Chicago's very own Glenside 
CoCo Club, who had assisted with many RainbowFests. 

page 18 

Tandy's Little Wonder 

Colorware, maker of CoCo Max, announced the arrival of 
Max-10 with a two page ad in Junes' Rainbow. Max-10 was 
similar to the Apple Maclntoshs' Mac Write word proces- 
sor. It was all graphics based with mouse controlled pull- 
down menus. Since graphics and text could be mixed, it was 
billed as a desktop publishing system when combined with 
CoCo Max 3 . Many different fonts and styles were available, 
and since all could be displayed on the graphics screen, Max- 
10 was the CoCos' first true WYSIWYG (what you see is 
what you get) word processor. The ad stated that Max-10 was 
not copy protected, but that wasn't entirely true. The disk 
itself had no copy protection, but a hardware Itey (the first 
and only one ever for a CoCo product) was included. This 
was a series of resistors and diodes which plugged into the 
cassette port. If the software didn't find it, it simply wouldn't 
run! Though the keys' components were cast into an opaque 
resin disk, hackers soon discovered how to mimic its signals 
and defeat the protection. Such an outcry was made over this 
new (to the CoCo world) protection scheme that Colorware 
soon dropped it in future versions. SD Enterprises released 
an updated VIP Database for the CoCo 3 in June. VIP 
Database owners could upgrade at a reduced price. 

THE NINTH YEAR (Jul '88 - Jun '89) 

In the beginning of the Rainbow's seventh year (CoCo's 
ninth), there are 79 advertisers. Many long time advertisers 
had started dropping support for the CoCo as their CoCo 1 
and 2 products became dated. They just didn't see putting in 
the effort to update (in many cases entirely re-write) pro- 
grams to take advantage of the many CoCo 3 features. 
Others, like Compute rware, who ran their last CoCo ad this 
month, expanded into more profitable computer fields. 
Paul Searby (owner of Computerware) redirected his pro- 
gramming efforts toward the popular IBM PC and com- 
patibles. Computerware had been one of the largest CoCo 
suppliers. Fortunately, many small newcomers were joining 
the programming ranks (which accounts partially for the 
large number of ads). Microcom became the largest adver- 
tiser with five entire pages. 

Several other interesting things happened in July of 1988. 
Windows came to Disk BASIC users through Cer-Comp's 
Window Master software. Up to 31 windows (even over- 
lapping!) with pull down menus could be controlled via a 
mouse/joystick or the keyboard on a 512K CoCo 3. 
Burke&Burke introduced R.S.B. (Radio Shack BASIC) 
for OS-9, which allowed pure Disk BASIC programs to run 
in a window under Level II. Lastly, Rainbow reviewed an- 
other desktop publishing package for the CoCo 3- this one 
from Tandy and operating under OS-9 Level II. Tandy's 
Home Publisher was a bit slow, but did do the job. The main 
gripe with this program was that it only supported Tandy 
DMP and Epson RX-80 printers. While most printers would 
operate with the RX-80 drivers, the RX-80 was getting a bit 
dated and newer printers were much better and had features 
the RX-80 driver wouldn't access. 

One of the first things that captured ones' attention in the 
August issue of Rainbow was a full page ad from Adventure 
Novel Software. In this unique ad, players of their new 
Night of the Living Dead interactive adventure game were 
offered $500 if they were the first to "survive". D.P. John- 
son introduced another programming language for OS-9 
users- FORTH09. This was a FORTH-83 standard imple- 
mentation specially tailored for OS-9 (level I or II, even for 
other OS-9 computers!). Help for users of Tandy's DCM 
Modem Pak was offered. The Modem Pak's primitive 
communications software does not allow for downloads or 
uploads (transfer of files from or to the host computer/ 
BBS). How to overcome this problem was the subject of an 
article by Delphi CoCo SIG database manager Don 

Even though Tandy was pushing OS-9 for software develop- 
ers, it dropped the RS-232 Pak, which was required for 
telecommunications under OS-9. It wasn't long before some- 
one, in this case Orion Technologies, introduced a directly 
compatible clone (October '88). Unlike other products 
(such as the Disto RS-232 Pack), Orion's pack had the same 
hardware address as the Tandy. Just plug it in and go! A 
version with external power supply was made for the CoCo 
2 and 3, or the standard version could be used with a CoCo 
1 or Multi-Pack, which provided the necessary 12 volts. 

Getting ready for Christmas, Diecom released several new 
games in November. Xenion ran on a CoCo 1 ,2, or 3 and was 
similar to the arcade game Xevious. Medieval Madness 
was another CoCo 3 only light phaser game. If one already 
had a Sega light phaser and interface from Iron Forest, the 
disk could be purchased alone. Microcom added a spelling 
checker, pop-up calculator, split-screen editing, and 
two column printing to Word Power release 3.2. 
Colorware started advertising their Max products (CoCo 
Max III and Max- 10) as the ideal desktop publishing package 
for the CoCo 3. Release 2.0 of SD Enterprises' VIP 
Writer III supports up to 495K of text space on a 512K 
CoCo 3 ( 1 06K on a 1 28K model), more than any other word 
processor to date. 

It was hard not to notice that Microcom had become the 
biggest CoCo advertiser ever- their ads were up to 6 pages in 
the December '88 Rainbow! They offered a wide variety of 
CoCo products from many different companies as well as 
their own software. A new offering was 512K BASIC for the 
CoCo 3 . When Tandy updated the CoCo's BASIC, they didn't 
allow easy access to more than 32K for BASIC programs. 
This product patched BASIC to allow access to 64K on a 
128K machine and 384K with 512K RAM. The only prob- 
lem was that one must have 512K BASIC in order to run a 
program that took advantage of the extra memory! 

Tandy's Little Wonder 

page 19 

What better time to advertise new products than the Christ- 
mas issue? Notable items were: 

* Warrior King (Sundog Systems) - a CoCo 3 fantasy 

* CoCo Graphics Designer Plus (Zebra Systems) - 
CoCo 1,2, & 3 were supported by this update of CoCo 
Graphics Designer. This was the closest thing to "Print Shop" 
available for the CoCo. Cards, signs, and banners could be 

* Start OS-9 (Kennetli-Leigh Enterprises) - A book that 
stepped one through the process of setting up and getting 
started with OS-9 Level II. A disk with several extra utilities 
was also included. This was the easiest to use guide to OS- 
9 ever. It was written like a text book in easy to follow steps. 

* Eliminator (Frank Hogg Labs) - A multi I/O card for 
the CoCo 3 and OS-9. Featured two serial ports, 1 parallel 
port, real time clock, plus a high speed floppy and hard disk 
interface. No more multi-pak cluttering up the desk... if one 
were an OS-9 user only! 

Colorware started advertising "THE WORKS" in the 

January 88 issue of Rainbow ("Your CoCo 3 will think it's a 
Mac"), intheirwords "The Ultimate in Desktop Publishing". 
THE WORKS included Max-10+ (with a spell checker 
added), CoCo Max III, and additional font sets for both. SD 
Enterprises introduced VIP Calc III this same month. As 
in other VIP products, 32-80 columns were supported. VIP 
Calc also offered up to 16 windows, which allowed easy 
comparisons, and a spreadsheet size of 512 columns by 
1024 rows. Owl-Ware purchased the rights to all CoCo 
products from J&M Systems and began advertising an 
improved disk controller based on the J&M design. The 
parallel port was missing, as was JDOS (OWLDOS or Disk 
BASIC are offered). Owl also introduced an IBM keyboard 
adapter for $119- more than a CoCo 3 (Computer Plus had 
them on sale for only $115 in the same issue), and without 
the keyboard! Zebra Systems had a cache of 500 64K CoCo 
2s to sale for only $49.95 (hurry while supplies last!). 

If you hadn't upgraded your CoCo yet or were thinking of 
buying a hard drive, the March issue of Rainbow was an issue 
not to miss. Marty Goodman went through RAM and ROM 
upgrades for all CoCos ever made. He also went on in 
another article to explain the ins and outs of adding a hard 
drive to a Color Computer system, not an easy task! 

Simply Better, from Simply Better Software, was intro- 
duced in an ad and review in the April issue of Rainbow. This 
word processor for the CoCo made quite an impact, being 
preferred over other word processors by the likes of Cray 
Augsburg (a Rainbow Technical Editor, who also wrote the 
review for this product) after using it only a short time. At a 
price of only $29.95, the review heading of "the most bang 
for your buck" was definitely true ! The author even prepared 
this text using Simply Better, which was purchased largely 
due to the review and a comparison article in the same 
months' Rainbow. 

The Chicago RainbowFest was held April 14-16 in 1989. 
JWT Enterprises introduced Nine-Times, a bi-monthly 
magazine on disk for OS-9. This would prove to be very 
popular for Level II users. Another new OS-9 item was Owl- 
Ware's Window Writer word processor. Unlike most 
other OS-9 word processing software, a separate editor and 
formatter were NOT used. Pull down menus were controlled 
either from the keyboard or with a mouse/joystick. 

An important issue in April's Rainbow editorial column 
(Print #-2) was the fact that the CoCo was being discontin- 
ued in Canada. InterTAN (an independent subsidiary of 
Tandy that handles overseas operations) had its own officers 
and stock, and also made its own decisions. One of those 
decisions was to discontinue CoCo sales in Canada. One 
reason for this decision was that many Canadians either 
drove across the border or ordered their CoCo supplies 
from American distributors, which lowered actual in Canada 
sales figures. The reason for doing this was the U.S. /Canada 
monetary exchange rate... CoCos were cheaper if bought in 
the U.S. Lonnie Falk encourage alarmed Canadian users to 
write InterTAN and encourage the return of CoCo support. 
Many were afraid the CoCo was being discontinued by 
Tandy. That was still a few years off.. 

May was Rainbow's printing issue, and desktop publishing 
was 1989s main feature. The three major desktop publishing 
packages for the CoCo (Newspaper Plus - Second City 
Software, The Works - Colorware, and Home PubUsher 
- Tandy) were reviewed and compared. A major enhance- 
ment for Rainbow's desktop publisher (written by H. Allen 
Curtiss, Oct. '87) was a high density printer driver written 
by the original author. Printouts were much improved over 
the original. This program was almost as good- if not AS 
good- as Tandy's Home Publisher. And speaking of bargains, 
Colorware put CoCo Max III and Max- 10 on sale for only 
$79.95 for BOTH if bought at the same time. Individual 
prices were $49.95 and $39.95 respectively. The Micro 
Works, makers of the video digitizer (Digisector DS-69 
& DS-69B) for the CoCo, ran its last ad in the Rainbow this 
month. The digitizers were still available from Colorware. 

Another product allowing the BASIC programmer access to 
more memory was introduced in June. Danosoft announced 
its BIG BASIC, which allowed access of up to 472K with a 
512K CoCo, 92K with a 128K machine. Only three new 
BASIC commands were required. One wonders why Tandy 
didn't do something like this! Like 512K BASIC from 
Microcom, a program written to take advantage of these new 
features meant that one had to also own a copy of BIG 
BASIC. That was the primary reason neither product was a 
real big seller. 

page 20 

THE TENTH YEAR (Jul '88 - Jun '90) 

July marked the tenth anniversary of the Color Computer. 
This was a milestone in the small computer industry. Only 
the Apple II and Commodore 64 remained alive along with 

Tandy's Little Wonder 

CoCo in what was once a teeming, competitive field. A new 
arrival this month was CIII Pages fi'om Microcom. As the 
name may suggest, CIII Pages was a yet another desktop 
publishing pacli^age for the CoCo 3. A new advertiser was 
Oblique Triad. Their premier products were The Seventh 
Link (a three disk graphic adventure game) and Studio 
Works (a digital audio sampler). 

What was probably the most welcomed new product. Ex- 
tended ADOS-3, was announced by Spectro Systems in 
August. Not a new version of ADOS-3, EADOS-3 shared 
wild cards, clock support, and many other features to ADOS- 
3. EADOS couldn't be run from disk (had to be EPROMed) 
and required ADOS-3. Another new item introduction was 
the RASCAN video digitizer sold by Microcom (CoCo 3 
only). This was similar to the MicroWorks DS-69 
Digisectors, but plugged into the joystick ports instead of 
the expansion port, eliminating the need for a Multi-Pak or 
Y-cable. The RASCAN was developed and made in Australia. 

Bill Chappie decided it was time to call and end to the 
publication of Dynamic Color News with the August issue. 
Circulation had dropped to just over 100 subscribers. The 
magazine, which peaked out with just over 200 subscribers 
at one time, had become to much of a draw on other business 
activities. It had never really made money, but hadn't been 
expected to do so anyway. The stated purpose of the maga- 
zine had been " . . . to provide instruction on BASIC & Machine 
Language programming, computer theory, operating tech- 
niques, computer expansion, plus provide answers to ques- 
tions..." These goals were certainly carried out! Thanks for a 
wonderful five and a half years of service Bill ! Though out of 
the magazine business. Dynamic Electronics would con- 
tinue (to this day) to support the CoCo with hard and soft 
ware products, including a large and inexpensive public 
domain software collection. 

By looking at the Advertisers Index of the September '89 
Rainbow one would think thatthe CoCo market was growing. 
The reverse was true- the format of the index was switched 
to multiple ad entries instead of a single entry with multiple 
pages for each advertiser. This gave the first impression that 
there were more advertisers when there were actually only 
52. Page count was down to 130, where it had been since 
August. The August '89 advertiser count was the lowest to 
date: 40. The highest advertiser count was in December of 
1985 at 142; highest page count was 288 pages in the same 

The Somerset RainbowFest was held October 20-22. 
This was the LAST RAINBOWFEST held in New Jersey. 
CoCo 3 s were being sold by Computer Plus for just $99! 
Tandy introduced several new ROM Pak games (Robocop, 
Rampage, Predator, and Arkanoid). Tony DiStefano of 
CRC Computers showed off a 1 megabyte upgrade pro- 
totype for the CoCo 3! Now OS-9 (the only product that 

could take advantage of the extra memory) could REALLY 
be shown off., as soon as it becomes available! Zebra 
Systems introduced their Label Designer, a graphics based 
point-and-click program that made cassette, Rolodex, disk, 
file folder, and normal address labels, and a graphics pro- 
gram similar to CoCo Max (Color Paint). The new Sundog 
Systems ad in this months' Rainbow introduced three new 
games (Sinistarr, Kyum-Gai to be Ninja, and Paladins' 
Legacy) and a sound editing/sequencing program 

In the November issue Rainbow decided to run a reader 
survey. All readers were encouraged to reply. The survey 
coincided with the promotion of Cray Augsburg, a former 
Rainbow technical editor, to the position of Managing 
Editor. Questions were asked about the reader him/her self 
and their system configuration. Readers were also asked to 
rank, in order of importance, certain topics and Rainbow 
columns. Congratulations Cray! 

The Print#-2 column in Decembers' Rainbow was very 
interesting. Mr. Falk was visited by Ed Juge, Tandy's 
Director of Market Planning. Readers were reassured 
that Tandy would continue the CoCo as long as it sold well, 
and reminded that it ALWAYS sold well during the Christ- 
mas holidays. A note about the InterTAN decision to drop the 
CoCo from Canadian distribution was also included. It 
seems that enough CoCo users wrote InterTAN that they 
decided to reintroduce the CoCo. Unfortunately, the pro- 
duction run for the season had ended, and InterTANs order 
was not large enough for another run. Readers were urged to 
write AGAIN, this time to encourage InterTAN to order as 
soon as the next run started. 

Something different appeared in this months Rainbow- an 
article by Tandy itself! Surprisingly, this article appeared 
due to a letter by a Rainbow reader. Back in May ' 89, a reader 
from Australia asked if there were an easy way to create new 
icons (graphics representing programs) for OS-9's Multi- 
Vue. Another reader replied in September, indicating that 
Tandy said "...Multi-Vue was originally intended for pro- 
gram developers...", and that a 10 page document addendum 
was available directly from Tandy. This prompted Tandy 
Computer Customer Relations to respond through a letter to 
the editor, stating that this impression about Multi-Vue was 
incorrect, the STYLE that Multi-Vues' documentation was 
written in was more suited to programmers. Tandy also 
offered "Multi-Vue and Pre-Existing Applications" (the 10 
page addendum referred to above) for publication in Rain- 
bow- it was published the very next month (December). 

The number of advertisers for the 1989 December issue was 
59. One of these, Orion Technologies, had an ad announc- 
ing a new hardware product for the CoCo- the XPort. This 
was a direct replacement for the Multi-Pak but with 
only three slots. These slots were on a short ribbon cable 
which came out of a box which contained the circuitry and 

Tandy's Little Wonder 

page 21 

plugged into the CoCo. A separate power supply provided 1 2 
volts to the slots. Also debuting was Howard Medical's 
MP-II, later called Slot-Pak II (possibly due to concern 
that Tandy might object to "Multi-Pak 11"). This was similar 
to the Xport, but built in a long disk controller case. Power 
for this multi-pak replacement was drawn directly from the 
CoCo, with an extra cost AC adapter for items that needed 
more power. The Slot-Pack II (or MP-II... whatever!) was 
designed by Chris Hawl^es, a well known hardware designer 
for the CoCo (one reason Chris is so well known is his 
physical height... if one ever meets him at a 'fest, they will 
never forget!). 

Microcom announced yet another improvement for its 
word processor- Word Power 3.3- in January. Now 40 and 
80 column displays were supported, and graphics could also 
be inserted in documents (CoCo Max, PMODE 3/4, and 
HSCREEN formats). Three new games. Overlord (wargame 
similar RISK), Defendroid (similar to the arcade game 
Defender), and Those Darn Marbles (roll a marble through 
mazes... not quite that easy!) were released by Oblique 

Lonnie Falk used the Prrnt#-2 column to announce plans for 
the publication of a book (due out in late summer/early fall) 
entitled "An Affectionate History Of The Tandy Color 
Computer". The authors of this book were to be Dale and 
Esther Puckett. Unfortunately, the book would never be 
printed. An interesting side note is that the book you read 
now may not have been printed had Rainbow printed their 
history. Rainbow later announced they would be interested 
in finding a new author. This author responded after some 
thought. The problem was that the Rainbow book was to be 
simply a collection of interesting anecdotes and memoirs 
from various CoCo personalities and a brief history. After 
some thought, and before Rainbow was contacted, this 
author had already decided that more than a simply history 
was needed. 

Hardware hackers would be well advised to get the March 
issue of Rainbow. Marty Goodman covered floppy disk 
drives for the CoCo, but the real hacker would be more 
interested in the Computerized Instruments projects. 
William Barden Jr. showed all how to turn CoCo into a 
dual-trace storage oscilloscope with a sampling rate of up 
to 6000 samples per second. Dennis Weide started his 
series on building a digital logic analyzer for testing and 
checking DIP type integrated circuits. An unusual ad prom- 
ising a new computer in 1990, a CoCo users "dream com- 
puter", was run by Kenneth-Leigh Enterprises this month. 
Just what would this "dream machine" be? No details were 
given, just encouragement to write for details! Rainbowfest 
Report covered the Oct Rainbowfest in New Jersey, and a 
tentative date (Oct. 20-22) for the next New Jersey 'Fest was 
set. The Chicago Rainbow fest would be next month! 

Chicago Rainbowfest was held (April 06-09). Two new 

computers, were shown. Kenneth-Leigh Enterprises was 
showing their yet to be named 68020 based machine 
while Frank Hogg had a 6809 based computer on display. 
These were basically prototypes... more to come on them 
later. Lee Veal turned up with an old grey original CoCo... 
serial number 000001 was engraved on the bottom! 

Not to be completely overshadowed by Rainbowfest was a 
small quarter-page ad in this months' Rainbow by a new 
company called CoCoPRO!. They offered good prices on 
hardware, and also something new in the CoCo market... 
"gently used" software (with original documentation, of 
course... no pirating here)! Another item of interest was that 
Danosoft had acquired the Simply Better word processor. 
One last thing for this month- Oblique Triad upgraded their 
Studio Works program to create Studio Works Profes- 
sional. New features include 35KHz 8 bit wide sampling, 
MIDI slave mode, and support for up to 1MB of memory. It 
seems that Orion Technologies had faded out of the CoCo 
market. Their last ad was run this month. 

With the introduction of Owl Ware's Window Writer 1.2 
in February, multi-lingual word processing arrived on the 
CoCo. This slightly updated version also featured a French 
edition. Why French? There has always been a relatively 
strong French-Canadian CoCo market segment. Also from 
Canada was Disto's new 1 megabyte upgrade! This was a 
board with a small amount of circuitry and 512K in 41256 
DRAM chips. The existing 512K board plugged into the 
1MB board. A small satellite board also had to be soldered 
"piggy -back" style over the CPU, as several control lines had 
to be picked up. Alternately, the CPU could be socketed and 
a socket installed on the satellite board to carry the CPU. 
Either way, only the competent "hacker" could install this 
memory upgrade. Disto also announced another "hardware" 
item- Tony DiStefano's "A Full Turn of the Screw" book, 
which reprinted all hardware articles published in Rainbow 
from January 1983 to July of 1989. 

This is the first (May 1990) of the 100 page Rainbows. 
There are only 46 advertisers. Sure is getting thin! Will the 
Rainbow fade away? In his editorial (Print #-2), Lonnie Falk 
is encouraging those who also have MS-DOS machines to 
try PCM. PCM was started two years after the Rainbow to 
support Tandy laptops and MS-DOS based computers. Is this 
a subtle hint? Maybe not... What's that on page 33? Another 
one of those odd Kenneth-Leigh Enterprises ads! This 
one promises "MS-DOS based applications multi-tasking 
alongside MIDI programs, in 256 colors and sound that 
surpasses CD quality." If you want to know the computers' 
name and price, you still have to write ! Budding astronomers 
could take advantage of their CoCos power to map the sky 
with Gravity Studios' Planet Engine. Maps could be made 
for any time/date... even with proper shadowing for phases! 

If you want to know how Tandy managed to squeeze up to 
1MB of data into a ROM Pak, then get the June issue of 

page 22 

Tandy's Little Wonder 

Rainbow. Frank Hogg Laboratories announced the Tom- 
cat TC9, a 6809 based computer that was 25% faster than 
the CoCo, used a PC/AT 101 key keyboard, up to 1MB of 
RAM, high resolution joystick, parallel port, two REAL 
serial ports (ACIA controlled), K-bus and CoCo bus 
expandability, and fit into a PC type case! With the K-bus, 
one could later add a 68xxx processor and use the TC9 board 
as a multi-function graphics coprocessor! This machine ran 
OS-9 Level II and Disk BASIC support was promised for 
the future. Rainbow lost two pages this month! Now it seems 
to be losing them one by one! 

THE ELEVENTH YEAR (Jul '90 - Jun '91) 

The eleventh year of the CoCo started a new look for the 
Rainbow, which celebrated it's ninth anniversary of CoCo 
support. Saddle stitch (stapled) binding was introduced. In 
his "Wrapping the Rainbow" column, Cray Augsburg pointed 
out that there were advantages to this type binding- the flat 
spine binding ("perfect" binding is the proper term) made it 
hard to lay the magazine out flat for typing in listings and 
pages could come lose with repeated use. These were good 
reasons for switching, but the cover up didn't fool a lot of 
readers. Perfect binding didn't look good with a thin maga- 
zine (only 98 pages!), and saddle stitch cheaper. Like the 
author, most readers were just happy to get the Rainbow. 

Several interesting ads appeared in the anniversary issue of 
Rainbow. A new one was from P&M Products. Their 
products were simple keyboard templates with the most 
used commands for BASIC (CoCo 1, 2 & 3) and Telewriter 
64 and 128. They simply laid around the keyboard! So 
simple, why didn't someone think of it sooner? Hey, Ken- 
neth-Leigh finally tells us the name of their new computer- 
the MM/1 (multi media 1). The company promises to tell 
more each month. This month they tell us that it uses existing 
CoCo disk drives and analog RGB monitor- saving some of 
our investment when (if) we decide to "upgrade" to the 
15MHz 68020 based system. 

A new magazine hit the scene in July. Entitled "The 
OSK'er", the publication proclaimed to have "news and 
views in the world of OS9/68000 and 6809". The premiere 
issue contained 24 pages (including both sides of the cover) 
in an 8 l/2"x 11" two column format on a high quality white 
(not slick) paper, saddle stitched (stapled). There were some 
highly unusual formatting standards used. The table of con- 
tents looked like a disk directory, the title of each article like 
a file description, and the pages were numbered as "sectors". 
The entire magazine read like an on-line conference! The 
most interesting articles were a Q&A session about the TC9, 
TC70, and MM/1, and a rather lengthy interview with 
Kevin Darling, which described when Kevin first got inter- 
ested in OS-9 (among other things!). The magazine was 
published by StG Computers, Inc., and edited by StG owner 
Scott Griepentrogg. 

In the August Print#-2 column, Lonnie discussed the arrival 
of the new computers. He predicted that they would be 
natural extensions of the present CoCo, possibly an accept- 
able upgrade path for many users. He also alludes to the 
possibility of there being several regional CoCoFests spon- 
sored by local groups, not Rainbow. This allusion is to the 
Atlanta CoCoFest sponsored by CoCoPRO! and the 
Atlanta Computer Society (ACS), a CoCo club in Atlanta, 
Georgia, being planned for October 6 & 7. Stated right out 
is that there would be NO NEW JERSEY COCOFEST 
sponsored by Rainbow. There would be a single Rainbow- 
Fest in Chicago during the spring. The Atlanta show (held at 
the Lakewood Holiday Inn) was advertised by CoCoPRO!, 
the primary sponsor, and also mentioned in the MM/ 1 ad. 

Hey! What's this! Not only do we now have a picture of the 
MM/1, but prices as well! A single floppy (1.4MB, 3.5") 
system without monitor (use your CM-8 or compatible!), 
but with OSK, BASIC, C compiler, and several other pro- 
grams and utilities cost $779. They would even be GIVING 
ONE AWAY at Atlanta! A new company name appeared in 
the MM/1 ad for the first time also- Interactive Media 
Systems (IMS). Not to be passed up, Frank Hogg bills his 
machine as "the CoCo 4 that Tandy should have made..." 
With the 6809 processor and genuine GIME chip, Frank is 
close to the truth in calling his machine a CoCo 4. The only 
thing missing is the promised Disk BASIC compatibility... 
Mr. Hogg also introduced a reference book for OS-9 
written by none other than Kevin DarUng. Inside OS-9 
Level II was not a replacement for the manual nor a tutorial, 
but a programming reference that really gets into OS-9 like 
no other. A disk full of patches and utilities was included. 
Kevin continues to support OS-9 and OSK (OS-9 for 68xxx 
processors) with his amazing programming prowess to this 
day. Keep up the good work Kevin... we need you! 

The August OSK'er had a few improvements. The most 
noticeable was a somewhat better font and normal headings 
for each article, though the letters section entries still 
looked as if they came straight from an electronic mail file. 
Another "quirk" that appeared on the cover was the volume 
number. It was described as "VER01.02" (version 01.02 - 
meaning volume 1 number 2). Interesting articles included 
specifications of the MM/1 and TC70 OSK machines, an 
article on "OS-9 In Industry", "Playing Chess in C" (the 
program was being written as the article progressed through 
multiple installments), and an article explaining just what the 
term "multi-media" meant. Letters were all encouraging. 

The CoCo and OS-9 SIGs (Special Interest Groups) on 
Delphi have always been great sources of up to the minute 
information, support, and software for CoCo users since 
their creation by Rainbow years ago. Price had been a major 
hurdle for many users of the low cost CoCo though. Until 
September of 1990, connect time cost was $7.20 an hour. 
This barrier was shattered when Delphi announced the 
"20/20 Advantage Plan". For $20 a month, a caller re- 

Tandy's Little Wonder 

page 23 

ceived 20 hours of on-line time. It isn't hard to see that this 
was a bargain! For what one would previously have paid for 
not quite three hours, 20 hours were available! If it could be 
considered a "catch", one had to pay $20 monthly regardless 
of how little time was used. Time over 20 hours would only 
be billed an additional $ 1 .20 per hour. If one does not belong 
to Delphi, well... you don't know what you are missing! 

IMS, in a bid to win over more users, began offering a short 
lived lease to own option in October. For as little as $56 
a month (with $ 11 2 down and approved credit), one could get 
a new MM/1. Owl-Ware tried to get into the upgrade game 
by offering an unusual system- a PC/AT clone! This ma- 
chine was packaged not only with MS-DOS but also with 
a UNIX clone (similar to OS-9) in an attempt to sway OS- 
9 users. Gravity Studio introduced something new for the 
CoCo... PICO CAD, a computer aided drafting (CAD) 
system. 3-D wire frame images could be assembled in full 
color with this system. The only drawback was that a pen- 
plotter that used the DM-PL plotting language was neces- 
sary for printing. NMSA computer group released a new 
hardware item- CAT. This was a PC/AT case modified to 
contain a CoCo, disk drives, power supply, and a special 
seven slot bus interface inside. Some CoCo users had 
already mounted their machines in modified or special built 
cases... this package would make such a chore much easier! 
A feature article in Rainbow was Spectra 3, a CoCo Max like 
graphics editor, just for the price of the magazine and a few 
hours of typing. One could always take the easy way out and 
purchase Rainbow on tape/disk or download from Delphi 

Frank Hogg also had something new to sell this month, the 
Tomcat TC70 computer. The TC70 was based on the 1 5MHz 
Signetics 68070 processor (Motorola 68020 clone) and 

also came with BASIC, C compiler, OSK, and various soft- 
ware and utilities. A floppy based system (1.4MB 3.5" drive, 
101 key keyboard, color monitor, 1.5MB RAM, 2 serial and 
1 parallel port, SCSI hard drive port, and built in DMA cost 
$1499.95. A similarly equipped MM/1 would cost $1495. 
The TC70 board can be used to upgrade the Tomcat system 
to a 68xxx processor if the TC9 is already owned. . . or buy the 
TC9 and upgrade when the money comes along ($999.95 for 
board and software only)! The TC9 board was upgraded to 
use two 5 12K SIMMs rather than DRAM chips and a CoCo 
type 5 12K board. The main board was also divided into two 
boards... a main processor board and a DAT board. The main 
board held all memory, but the DAT board was required to 
use the second 512K. This was done to decrease the cost of 
a basic system, which could also be used as a low cost 
terminal for more expensive multi-user computers. 

Almost forgot... the first ever Atlanta CoCoFest was held 
in October! I was there! The show turned out to be a big 
success with many vendors and lookers alike. CoCoPRO! 
had a LARGE booth in the center of the main show floor with 
floods of used and old stock Tandy software. They even had 

some rare scenery disks for Flight Sim II (Japan scenery), 
which was selling for only $9.95 (the scenery disk was 
selling for more at $24.95) and OS-9 Level 2 for only 
$34.95! A new game, made especially for the fest, was 
available from CoCoPRO! also. In Marty's Nightmare, 
starring Marty Goodman (well, at least a good caricature 
of him!) had to search through a maze for a lost seminar! This 
neat software tribute to the good doctor was programmed by 
none other than Steve Bjork! Highlights of the 'fest in- 
cluded seminars by Steve Bjork (history and development 
of the CoCo), Cray Augsburg (Rainbow managing editor, 
on happenings at Falsoft concerning the Rainbow), and a 
Q&A type meeting with Kevin Darling that lasted four 
hours! Good thing it was the last one! The manufacturers of 
the three "new" OSK machines were actually grouped to- 
gether at a single seminar Sunday. After giving a brief 
introduction, questions flew concerning all three machines 
and their differences. Several notes of interest came from 
Grays' seminar- 1) Rainbow WOULD NOT be folded into 
PCM, 2) there would be a Chicago Fest sponsored by 
Rainbow next year, 3) the "new" computers WOULD be 
covered. . . as they became available to the general public, and 
4) the planned CoCo history book project was being can- 
celled due to lack of time by the author. The Atlanta Com- 
puter Society tookcare of doorprizes and assisted CoCoPRO ! 
with running the operation. Good work guys, can't wait until 
next year! 

October must end with a sad note. Color Computing 
magazine (changed in June from TRS-80 Computing) sent 
out what would be its last issue. Editors Joseph Ahern and 
David McNally were now freshmen in college and unable to 
spend much time putting a magazine together. The magazine 
had really grown, both in quality and size. From a few page, 
hand cobbled newsletter to a 34 page magazine, these two 
young men really put forth a memorable effort. Though 
circulation only reached a maximum of about 100 at any 
given time, they had put out a commendable effort for the 
past four years The only break in publication had been 
between June 91 and this last issue. Good luck boys (no, 
men!), and thanks for the support! 

The September issue of OSK'er was late. It actually arrived 
at most subscribers' homes in mid October! Aside from that 
forgivable incident, it was a very good issue. One reason for 
the lateness was the Atlanta CoCoFest (October 5-6). Scott 
went to the 'fest for a look-see and covered it nicely in the 

Ah, nothing like Christmas with the CoCo! Tandy started 
their 1990 holiday season sale in November with CoCos 
going for only $99.95, CM-8 monitors for $179.95, and 
drive systems for $199.95! Heck, I remember when a 4K 
CoCo costs nearly as much as all that COMBINED. Sundog 
Systems introduced several new games this month: The 
Quest for Thelda (graphics adventure). The Contras (mili- 
tary role playing game... an early announcement, wouldn't 

page 24 

Tandy's Little Wonder 

actually be ready until 1993!), Crystal City (classic space 
shoot 'em up), and Zenix (similar to original space invaders, 
but much more action!). All of these games featured supe- 
rior graphics, sound, and animation, especially when viewed 
on an RGB monitor. Burke&Burke had something new for 
OS-9 users- a speech synthesizer called Cyber Voice 
which used a SC-02 synthesizer chip. 

The December Rainbow has Lonnie squelching rumors 
of the Rainbows demise. He states that "There is no 
intention, plan, idea, concept, or anything of the kind to 
cease publication of the Rainbow. I don't know how 
these rumors get started." Well, one way is the shrinking 
size and number of advertisers (still 98 pages, 47 advertis- 
ers). He reassured readers that there would be a Rainbow for 
some time, and that there would be a spring 'fest in Chicago. 
"Some time" was still two and a half years away... Many 
readers complained about no rack seller availability. This 
was due to cutting back the number of rack sellers. Why? 
Rainbow actually took a LOSS on many single-issue sales 
due to support of many locations that only sold a few copies 
monthly. Only those outlets with good sales would be 
supported from then on. Perfect time to save money and get 
a subscription ! A new version of the Slot Pack, Slot Pack III, 
was introduced by Howard Medical. A hardware switch 
was added to allow use of most ROM packs in slot 1, a leg 
added to support the pack, faster buffer chips used, and an 
external power supply became necessary, as the draw 
from the CoCo was just to much. 

If you have ever considered recording CoCo screens on 
video tape or using some of the CoCos abilities in your 
home movies, then do get a copy of the December 90 issue. 
An article by Mark Haverstock and Bill Wills shows how. 
An article by Andrew T. Boudreaux, Jr., tells how the New 
Orleans CoCo Users Group made a show on the CoCo 
through a local cable community access channel. The 
group even used their CoCos for several required functions 
such as headers, title screens, and prompters. It's here- 
CoCo TV! A new CoCo book was reviewed this month. 
"Connecting CoCo to the Real World" was written by 
William Barden, Jr., a Rainbow contributing editor. The 
focus was on connecting the CoCo, mainly through the 
joystick ports, to many items. Projects included a burglar 
alarm and weather station. If one can find the book it is very 
interesting and the projects pretty easy to build. Unfortu- 
nately, Mr. Barden left the CoCo community shortly after 
releasing the book. Worse, he seems to have left on a sour 
note... or at least left some CoCo users who ordered his book 
that way. The author was one of several who ordered the book 
and never received it, yet had their check cashed. Inquiries 
were left unanswered. Luckily, few CoCo vendors, who rely 
on mail order, leave us in this manner... most are VERY 
reliable! Who would have thought this of Bill? If there was 
extenuating circumstances unknown to us I apologize in 
advance for including this here, but we who ordered were at 
least due an explanation, and a refund. And sadly, yet another 

advertiser falls out as the last Second City Software ad 

appears. But take heart! They aren't leaving the CoCo mar- 
ket, just moving operations and changing name to Kala 
Software. Unfortunately, Rainbow ads won't be in the "new" 
companies' future any time soon. 

Hardly anyone noticed that the last Computer Island ad 
appeared in the October '90 issue of Rainbow. Nor that the 
last article written by Steve Blyn (a contributing editor 
since July 1982 with his Education Notes column) ap- 
peared in November. This was brought to their attention by 
Lonnie Falk in the January 1991 issue. Steve wrote a very 
good letter explaining that orders were slow and the opera- 
tion was winding down. Lonnie publicly thanked Steve and 
his wife Cheryl for the many contributions to the CoCo 
community and wished them luck... from ALL of us! In this 
case, Lonnie definitely spoke for at least most longtime 
Rainbow readers. Well, at least there is some good news, as 
the first ad from Rick's Computer Enterprises appears. 
Several programs are offered, but the most interesting is 
The Rainbow Indexes, a database of all Rainbows since the 
original and promised to be updated annually. Now if one 
needed to refer to an old article, simply boot the program and 
search! No more thumbing through the anniversary/index 
issues! Thanks Rick, we needed something like this! 

Not all was doom and gloom in January! Zebra Systems 
introduced First Prize, an award certificate making pro- 
gram for the CoCo 2 or 3. This useful program came on SIX 
diskettes, complete with storage box! Like other Zebra 
software. First Prize operated in an easy to use point and 
click graphics environment. CoCoPRO! came through the 
fest with some leftover Japan scenery disks. Flight Sim II, 
OS-9 Level 2, and Marty's Nightmare games. Those who 
didn't attend the fest were now able to purchase these 
bargains. The IMS ads featured an interesting twist: an MM/ 
1 could now be purchased as a kit (add your own case, 
keyboard, monitor, and drives) for $659, a savings of $120. 
One reason for the kit was delays in meeting FCC re- 
quirements for full systems, which was causing serious 
delivery delays. Many people who had made down payments 
were wondering if they would ever get anything! Kits could 
be sold without FCC certification. Delphi users would 
notice lower rates in their ad ($6/hour), and also discover 
that Marty Goodman is the CoCo SIG manager! And what 
is that on page 33? A System IV computer from Delmar 
Company! I remember! This was a THIRD 68xxx based, 
OSK computer system which first came to light at the 
Atlanta CoCoFest, which was only fitting, since Peripheral 
Technologies of Atlanta builds the boards! These ma- 
chines used a 16MHz 68000 chip and a PC/XT 8 bit 
expansion bus. The PC/XT bus was used due to the availabil- 
ity of cheap expansion cards. A base model with four serial 
ports, a parallel port, 1.4MB 3.5" floppy drive, 40MB hard 
drive, case, keyboard, OSK operating system, and mono- 
chrome monitor sold for $1399. Delmar sold complete 
systems, kits were available directly from Peripheral 

Tandy's Little Wonder 

page 25 

Technologies. This computer had been in existence for 
several years. It actually started as a build it yourself project 
in an electronics magazine several years before., sort of like 
the original hobbyists computer- the Altair (anyone reading 
this even remember one of those?). 

The ads were interesting in Februarys' Rainbow. The first 
thing one will notice was that longtime advertiser Microcom 
only had two pages. Didn't they ALWAYS have six before? 
Are they fading away also? The last Howard Medical and 
last Dr. Preble's Programs ads appeared this month. 
Thanks go to Ross Litton (Howard Medical) and Dr. Preble 
(he was actually a Dentist!) for the many years of good 
service. The MM/1 had only two quarter page ads this time. 
Maybe the "new CoCo" isn't doing so well after all... (previ- 
ous ads were one and two pagers). But here to save us from 
all this gloom is the rising star of the CoCo community- 
CoCoPRO! New this month was an OS-9 version of Kyum- 
Gai, to be Ninja. Though many critics thought OS-9 was not 
a good environment for action graphic games, they were 
proven wrong, as the two versions of Kyum-Gai were nearly 
indistinguishable. There were only 30 copies of Marty's 
Nightmare left now... better hurry! Last but not least, Tandy 
announced a CoCo "blow-out" sale on the back cover. 
CoCo 3s could be purchased for $99.95, CM-8 monitors 
and single disk drive systems for $149.95. 

Marty Goodman told all about monitors for the CoCo in 
March. This was also the thinnest Rainbow yet- only 82 
pages! CoCoPRO! ads grew to 1/2 page. They offered Tandy 
Orchestra-90 paks for only $17.95 (was $79.95) and "Where 
in the World is Carmen Sandiago" for only $15.95 (was 
$34.95). Sadly, another supplier is lost as Danosoft runs 
their last ad. Rainbow stopped shipping the magazine in 
plastic bags this month. Cray Augsburg said it didn't 
significantly reduce complaints about mangled magazines in 
the mail, but most subscribers realize it was mainly a cost 
cutting measure. Better the bag than more pages! 

A new serial pack was introduced in the April CoCoPRO! 
ad. It was a conversion of the Tandy 300 baud DC Modem 

Pak, which contained most of the circuitry for a true serial 
port. The modification was designed by Marty Goodman. 
A completed pack or kit was offered. The company ad was up 
to a full page in May. Soft and hard ware from several 
companies was brought on line. There were only 23 other 
advertisers. A new piece of hardware came to light in May 
also the Delta Pro sound device by Lucas Industries 2000. 
The Delta Pro used the delta, or change, method of recording 
sound. Digitized sound was now possible with minimum 
memory usage. H. Allen Curtiss' desktop publishing 
program was updated beginning this month into Ultralace, 
which would run on the CoCo 3 only. The updates would 
occur over the next several months, as the program was 
almost totally re-written to take advantage of CoCo 3 fea- 
tures and for higher resolution printing. 

April 26-28 was the time for the last Rainbowfest (held 
in Chicago). Radio Shack took up almost a fifth of the 
floor space! They were selling CoCo 3s for $80, OS-9 
Level II for $40, and lots of OS-9 based software for $5 
and $10! The final hours of the last day saw Tandy selling 
CoCo 3s for only $60... guess they didn't want to load them 
back in the truck! Many vendors were there showing their 
wares, including the three OSK machines. Delmar and FHL 
displayed actual production models, while IMS still had a 
prototype. Developmental delays, including FCC certifi- 
cation problems, had delayed production. Many people were 
upset, but they were continually reassured that the computer 
WOULD eventually come and the fact that the company was 
showing up at the Tests at least let everyone know they still 
existed. Lonnie Falk moderated a question and answer 
seminar between Ed Gresick (Delmar), Paul Ward (IMS), 
and Frank Hogg (FHL) concerning the three OSK ma- 
chines. Seems that interest in these "new" machines is pretty 
high. Wonder if I should consider making the switch? Guess 
I should try learning OS-9 on my CoCo first! Soon after this 
'fest, Tandy started selUng most OS-9 software, includ- 
ing Level II, the Development System (assembler), and 
C compiler for $5-$10 nationwide (they were let go at 
that price during the fest also). Interestingly, Multi-Vue 
continued to carry a $49 price tag. These bargains were 
not advertised, but once they were found out, things went 
FAST ! It was becoming hard to find CoCos and related hard/ 
software in Radio Shack stores. The end had finally come. 
Many CoCo 3s were made before the Christmas season, and 
there were plenty... to many... left. No more CoCos would 
ever be produced. 

Careful readers should have noticed by now that there has 
been no mention of OSK'er for five months. The reason is 
that they mysteriously disappeared! The fourth issue finally 
reached subscribers in May. Understandably, the editor 
decided to leave a date off the cover. In this case, the 
directory format of the table of contents comes in handy- the 
editorial was last modified on April 23rd, 1991. This 
lapse of coverage with no notice to subscribers was inexcus- 
able and hurt the reputation of both the magazine and editor. 
The editor realized this, and wrote an apologetic editorial 
about missing deadlines. It seems that a big reason for the 
lapse in issues was that the company (StG Computers) 
moved locations. He also stated that "OSK'er (was) back 
for good". To bad that would not prove to be a true 
statement. On the plus side, a good article on BASIC09 
(Introduction to BASIC09) appeared in this issue. 

It didn't take one long to notice that there was no Microcom 
ad in the June Rainbow! Last month it was SD Enterprises, 
distributor of the VIP series. Is one of the largest CoCo 
suppliers leaving? Lonnie lets us all know not to expect to 
find Rainbow on many newsstands. These sales were never 
high, but many were kept up because one could walk out of 
a nearby Radio Shack with a CoCo and pick up a magazine- 
this was now next to impossible. Only those stands with 

page 26 

Tandy's Little Wonder 

"historic" high demand would from now on be supported. 
Frank Hogg, who had a few troubles with the slow moving 
TC9, came out with the Tiger lOMHz 68000 based pro- 
cessor board. This was basically a coprocessor for the 
TC9 that would speed execution of OS-9 Level II by a factor 
of two or three. OSK could be purchased and run later with 
the addition of other K-bus boards. A low price of $129.95 
made this an affordable alternative to the much more expen- 
sive TC70. Burke&Burke introduced an update to the 
Tandy Cyrus chess cartridge. The update allowed transfer- 
ring the cartridge to disk and running under OS-9! Mouse, 
disk, and windows support was also added. The Cyrus pro- 
gram is still considered the best ever chess for the CoCo. 

An issue of OSK'er appeared... well it either appeared in 
June or July, or was it August? This time the table of contents 
didn't even reflect a date (that little item was probably 
overlooked in the last issue, not this one!). The MM/1 was 
finally reviewed, and promises of reviews for the Tom Cat 
computers were made for "next month" (no one was going to 
hold their breath for that!). The Rainbowfest was also cov- 
ered in detail. The "Flame ON" column featured an article 
entitled "Why the 'CoCo 4' Will FaU". The author, Jim 
Hutchins, pointed out various shortcomings of the new 
machines, their targeted market, and OSK support in gen- 
eral. An example was system cost. Any of the three OSK 
machines would run around $1300, while a comparably 
equipped AT clone would only have cost $1000. A rebuttal 
by Paul K. Ward (IMS) was also printed in the same 
column. A big point made about price was that the MM/1 
would be better compared against at least a 386SX based 
machine, and that the MM/1 has a built-in network interface 
which would cost extra for an IBM clone. Operating system 
cost was also mentioned. One would really need a version of 
UNIX (or OS/9000) to equal the windowing and multi- 
tasking/user capability of a 68xxx based machine. The oper- 
ating system alone would addover$300 to the 386SX price! 
No hint was given that OSK'er would expire, it just never 
appeared in a mailbox again. The final issue was printed 
several months later, much improved in appearance and 
even on "slick" paper. It was definitely the last. That makes 
six issues for the $12 subscription price... fair enough, even 
though twelve were initially promised. Putting out a maga- 
zine is a lot of time consuming, costly work (as this author 
will soon find out)! 

surely losing support! Don't worry to much, a lot of the old 
ones are still out there ready to sell. The problem was that it 
a quarter page ad in Rainbow cost around $300. Sales 
were falling to a level that could not support these rates for 
many suppliers. And pages were down to only 66. 

A full page ad appeared in the August '91 Rainbow for the 
CoCoPRO! sponsored, Atlanta Computer Society hosted. 
Second Annual Atlanta CoCoFest. It would be held in 
October (5-6). Hmmm... must make plans to be there! Anew 
CoCoPRO! product is Newspaper 09, a desktop publish- 
ing package for OS-9 Level II. It is based on Newspaper 
Plus. Lonnie used his PRINT#-2 column to review the 
Chicago fest of last April, no pages taken up by a "real" 
Rainbowfest Report as before. He states that coverage may 
be coming for the new 68xxx based machines, and that 
review machines were expected soon. The Delmar Sys- 
tem IV was even included in the "Received and Certified" 
section! The very last Microcom ad ran this month. They 
will be missed, but not for long... they go out by creating a 
small stir in the next few months... 

Gracing the front cover of Septembers' Rainbow was 

none other than the Delmar System IV received last month! 
Because of high interest, this review item was given a high 
priority. Readers found that the PT68K/4 motherboard 
used 8 bit PC/XT compatible cards (though drivers may 
not be available for some) and a 16MHz 68000 processor, 
all neatly packaged in a PC type case. A CoCo 3 was 
connected to one of the four serial ports as a terminal. It was 
remarked that this would be an excellent way to continue 
using existing software until OSK software could be pur- 
chased. The PT68K/4 does not come with BASIC, so the 
reviewing staff contacted Microware and received a copy 
for review, along with an integrated package (word pro- 
cessor, spreadsheet, and database) called SMART. Both 
had high price tags- $500 for BASIC and $895 for 
SMART. It was discovered that terminals running from the 
serial ports required VT-100 emulation. A prototype 
8086 based card was shown. This would allow running MS- 
DOS software, but not simultaneously with OSK. A "new era" 
of computing was coming... at least for OS-9 enthusiasts. 
With the passing of Danosoft, CoCoPRO ! picked up the 
rights of Simply Better. They advertised it on sale for 
$29.95... "the BEST CC3 word processor ever" (I have to 
admit some bias here- SB was used to write this book!). 

THE TWELFTH YEAR (Jul '91 - Jun '92) 

Whew! Microcom is back with a one page ad! Well, at least 
they are back with us... that one missed issue was a scare! 
Lonnie recognized a special person (which hardly anyone 
will even know) in his column in this 11th anniversary 
(Rainbows, CoCo is 12!) issue- Steve Ostrom. Who is this? 
One who had continually subscribed to the Rainbow for 
the entire eleven years... can one be more loyal? Remem- 
ber the CoCoPRO! modem pal</RS-232 serial conver- 
sion? Marty Goodman showed how it was done in this 
issue. Advertisers are down to only 21. We are slowly but 

Tandy's Little Wonder 

In October, Lonnie tells us that there was an example of all 
three "new CoCos" in the hands of the Rainbow technical 
staff Coverage of the new machines was planned, but only 
"as we see evidence of 'upward' migration to these systems". 
The CoCo would still be covered, of course. Marty Good- 
man authored an article explaining exactly why the Tandy 
Multi-Pak Interface (MPI) required updating for the 
CoCo 3 Older models (grey case) had to be upgraded to use 
the disk controller because the GIME chip in the CoCo 3 
used an address which would cause an unmodified MPI to 

page 27 

switch away from slot 4 (which contains the disk controller). 
The newer models (large and small white cased) appeared to 
work just fine in most cases. Intermittent problems resulted 
from the 6809 trying to read data from certain GIME port 
addresses. The main problem was that the MPI was designed 
before the CoCo 3 and the data buffer is activated whenever 
a read was performed in that overlapping address range ! The 
GIME and buffer would then try to give the 6809 data at the 
same time, garbling the read data. This would happen even if 
nothing was in the MPI. Upgrading the large MPIs was easy- 
order a replacement PAL chip from Tandy. Upgrade instruc- 
tions were given for the newest 26-3 124 (small white) MPI, 
which required the addition of a single chip and a few jumper 
wires. Tips were also given for modifying the MPI for OS- 
9 use (not required, but some modifications enhance opera- 
tions under OS-9). The IMS ad focussed on software com- 
panies with OSK software. A phone number for Kala Soft- 
ware, formerly Second City, was given with the advice to 
call for a catalog. Yes, owner Ed Hathaway still supported 
the CoCo (though it wasn't mentioned in the ad). Many of the 
other vendors mentioned as "gone" were also still in the 
CoCo business, there just wasn't enough of it to pay for 
Rainbow ads (remember... around $300 monthly for 1/4 
page) and make a decent profit... in many cases, not enough 
to break even! To top the month off (actually to START it 
off!), the Second Annual Atlanta CoCoFest was deemed 
a success again. There were fewer people than the crowd the 
year before, but still enough to make an effort for next year. 
With the sluggishness of the economy in general, the smaller 
showing was no big surprise. 

Gracing the cover in November was the 6809 based TC9 
Tomcat from Frank Hogg Laboratories. Until now, the 
TC9 design had been subject to several changes. The design 
reviewed was the production model then being shipped. The 
motherboard contained the 68B09 and a genuine GIME to 
maintain CoCo 3 compatibility. The CPU had to be run at just 
under 2MHz... the GIME wouldn't run at a full 2MHz! A 
pair of 256Kx8bit SIMMs (single in-line memory modules) 
took care of the 512K of memory. An additional pair could 
be added along with a DAT board (which handles address 
translation) for a full 1MB of RAM. The CoCo bus was a 
two-row 40 pin header connector. A short Y cable was 
connected to this. Unlike the CoCo, this bus was fully 
buffered so running with a Y cable would not strain the bus- 
nor the 200 watt power supply. Composite video and RGB 
was available, but no TV output. Two serial and one parallel 
port, the CoCo bus, and joystick ports were on an I/O board 
mounted above the motherboard. The only real incompat- 
ibility with CoCo OS-9 hardware was that a different ad- 
dress had to be used for the sound port. Three bytes had 
to be changed in Kyum-Gai in order to here the sound 
effects. OS-9 Level II had to be purchased separately from 
Tandy or another source. New boot disks with the correct 
FHL TC9 drivers had to be made with a CoCo 3 or the 
original OS-9 disks sent to FHL so they could make a new 
boot for the TC9 purchaser. Disk BASIC was not yet sup- 

ported, but FHL did release a utility within a year that 
allowed saving ones' CoCo 3 ROMs to disk and patched 
them for TC9 use, thus gaining Disk BASIC compatibility- 
but only if one had access to a CoCo 3 (note: it would be 
considered piracy if one did not own a CoCo 3). Rainbow 
shrank yet again- down to 50 pages and 20 advertisers. 
Two letters were printed from readers who had trouble 
with support from Microcom. They were still shipping 
orders for Word Power 3.3 but were NOT returning 
letters asking for support even after repeated queries. A 
sad way to end what was once a well respected company... 

And finally- a review of the IMS MM/1, with an appearance 
on the cover of the December '91 Rainbow! This computer 
is "brained" with a Phillips/Signetics 68070 (Motorola 
68020 compatible... manufactured for Phillips, the lic- 
ensee, by Signetics) and a 66470 Video System Controller 
(VSC). Due to delays in FCC certification, the MM/1 was 
being deUvered only as a "kit". The kit included a com- 
pleted motherboard, case, power supply, keyboard, I/O board, 
and drives. Assembly took only 30 minutes. Anyone who had 
ever installed a second drive in their CoCo could accomplish 
this task easily ! One serial, RGB analog video, keyboard (XT 
type), and sound ports were on the motherboard along with 
1MB of RAM, two ROMs, and the CPU and VSC chips. The 
I/O board had a second serial, a parallel, stereo sound, and 
joystick ports along with an SCSI interface (primarily for 
hard drives) and sockets for two 1MB SIMMs for a total of 
3MB RAM. The VSC chip supported an interlace mode 
which allowed crisp 16 or 256 color graphics with up to 
720x480 resolution (16 colors in 720x480 mode)- even 
on a CM-8! Real-time animation sequences were also 
possible. These last two items (high resolution graphics and 
animation) were both made possible by the capabilities of 
the VSC chip. Of all the new machines, the MM/1 seemed 
to have left the greatest impression. New this month from 
Sundog was Photon (a maze game). War Monger (war 
game, sort of a modernized version of Risk), and Graf 
Express (a graphics and music programming environment 
that allowed easy fast action and sound). Licensing options 
would be available for programs using Graf Express. 

The February and March 1 992 Rainbows were significant in 
one way: February was the last magazine format Rain- 
bow, and March the first tabloid, or newspaper, format. 

The reason for the change was simple economics. With 
fewer advertisers there wasn't as much money flowing to 
stay with the comparatively expensive slick paper color 
cover magazine. Rather than raise subscription prices ($3 1 
for a 50 page magazine isn't cheap!), the new format was 
chosen. The "new" Rainbow featured only 32 pages, but 
space was actually INCREASED by roughly nine percent due 
to the increase in size of the pages themselves. A four 
color process was still used for the cover, but most of the 
cover space was used for content rather than just "window 
dressing". The ads were bigger and the ad prices were even 
rolled back to the previous years rates. Ad price was a big 

page 28 

Tandy's Little Wonder 

issue (sore spot!) for many advertisers, especially with the 
cheaper to produce tabloid format. The "magazine" was now 
the size of many small town newspapers (and we all know 
how much they cost). The Rainbow has many more expenses 
than a small newspaper, but many advertisers (including 
some with printing industry connections) felt the current 
subscription price alone should come close to supporting 
the magazine- the ad rates were bordering on outrageous 
(still around $300 for 1/4 page). Only the fact that the 
Rainbow was still the only vehicle for reaching the majority 
of CoCo users kept the few advertisers (only 1 8 this issue) 
in those pages. If you were looking for a disk drive system, 
you would be in for a search- Computer Plus listed them as 
SOLD OUT (though a Tandy disk controller was still avail- 
able)! They had last advertised the CoCo 3 in January '91 
for only $89. 

Another supplier "bit the dust" in April '92- sort of. 
CoCoPRO! acquired all inventory and rights to the 
entire Howard Medical line. CoCoPRO! stated that all 
outstanding warranties would also be picked up in the trans- 
fer. The last Howard Medical ad had run in January '91. 
With no Rainbow support, CoCoPRO! again picked up 
organization of the Chicago CoCoFest, first advertised in 
this issue. This fest is being billed as the "First Annual 
'Last' CoCoFest" (May 30-31). Not that it will be the last, 
but only time will tell unless users keep up support! Dave 
Meyers is starting to show a little strain from organizing 
these events. Glenside will again be supporting Dave as they 
have always supported Rainbow, and may pickup organizing 
the next Chicago event altogether, as ACS will be doing the 
next Atlanta event. The only thing missing from the non- 
Rainbow sponsored events was the Rainbow itself (with the 
exception of the October '90 Atlanta CoCoFest). One can 
understand their inability to organize these affairs out of 
their home state, but it is hard to understand that the maga- 
zine won't at least support the fests by having a booth or at 
least covering them in the magazine. These events are of 
great interest to the CoCo community, as many new and old 
supporters often showed up to display their wares. And 
anything good for the CoCo community would also have 
been good for the Rainbow. 

Lonnie started quite a controversy in May. He stated that 
Rainbow WOULD NOT be supporting the new 68xxx 
based computers based mostly on the fact that software was 
either unavailable, hard to come by, or to expensive for most 
home users (remember $500 BASIC?). What REALLY 
vexed many people was that he recommended buying an 
INTEL based PC if one really needed a new computer. 
While this would be a logical choice for most users, the OS- 
9 community reaUy got upset! NOTHING on an MS-DOS 
based PC came very close to the power of OS-9 on one of the 
new machines (except maybe Microware's OS-9000, OS- 
9 for a PC type 386 or higher processor, but it was to 
expensive for real consideration), especially when the amount 
of investment is considered. That a special offer for PCM 

(Falsoft's PC magazine) followed the above statements 
made it seem as though he were steering one toward MS- 
DOS because he also published an MS-DOS magazine simi- 
lar to the old Rainbow (this was not, however, the case). A 
feature article by Bill Palmer told how to use a Hewlett- 
Packard DeskJet printer with a CoCo. These high resolu- 
tion Inkjet printers produce laser quality print and graphics 
without sophisticated software features at half the price (or 
less) of an expensive laser. H. Allen Curtiss was at his 
Ultralace desktop publishing system again, correcting 
some problems and adding some new features. His desktop 
publisher appeared to be one of the most popular Rainbow 
programs yet! A new Zebra Systems ad (they had been 
absent for two months- was starting to be concerned!) 
indicated that they had gained rights to the POKES, PEEKS 
'N EXECS books previously from Microcom. An ad for a 
new magazine, "The 68XXX Machines", couldn't have 
been better timed, considering Lonnies' editorial! At only 
$ 14.75 for a one year subscription, it was worth looking into 
if one was considering a 68000 based computer. A new ad 
from FARNA Systems appeared that not only advertised 
software, but also advertised space! Since Rainbow ads 
were so costly, why not sublet advertising space at a more 
reasonable rate? The idea was to purchase a large block of 
space at a better rate than a small ad, then spread the cost over 
many small advertisers. The idea was sound in principal, but 
not enough advertisers were interested to continue for long. 
CoCoPRO ! had a full page ad for the " Second Annual Last 
Chicago CoCoFest" held this month (May 30-31) that 
included directions for getting to the Inland Meeting Center, 
where the fest was held. 

Burke&Burke introduced their PowerBoost in June. This 
software/hardware combo included a Hitachi 63B09E pro- 
cessor chip and drivers for OS-9 Level II. The Hitachi 
processor was a 68B09E clone in CMOS architecture, but 
with some advanced features. These advanced features were 
taken advantage of by the new OS-9 modules and patches, 
providing an average 40% increase in speed while main- 
taining direct compatibility. A 6809 could be directly re- 
placed with a 6309 without the user knowing any difference. 
The new software, and the enhanced mode of the 6309, was 
the secret! A book describing the newly found "secrets" of 
this CPU was also available from B&B. 

What's this? A NEW MAGAZINE! The first issue of "The 
OS-9 Underground, Magazine Dedicated to OS-9/OSK 
Users Everywhere" was sent out in June. The cover fea- 
tured a 6309 chip on wheels being driven by a CoCo driver! 
The 40 page magazine featured advertisements from eight 
companies, most notable being Delmar (System IV com- 
puter). It was printed in a 5 l/2"x 8 1/2" format, saddle 
stitched (stapled). Although the print was a little small, it was 
exceptionally well laid out and professional looking with 
multiple fonts. No wonder! The editor (Alan Sheltra) was 
a graphics artist by trade ! Articles included "Test Driving the 
6309", and "BASIC Training". A classified section was also 

Tandy's Little Wonder 

page 29 

carried. The cover was a bright yellow, which certainly added 
to the magazines' visual impact. Subscription price (US) 
was only $18 for a year, cover price $2 per issue. 

The new OS-9 Users Group was officially formed in June 
'92. The new group picked up where the old left off, keeping 
many of the same goals and even the same name for the 
newsletter (MOTD . . . "Message of the Day " . . . what users first 
see when signing on a multi-user OS-9 system). Elected 
president of the new group was Boisy Pitre, vice presi- 
dent Carl Kreider. 

THE THIRTEENTH YEAR (Jul '92 - Jun '93) 

Lonnie Falk made an understatement in July's Print#-2 
column- "... it seems I have stirred up something of a hornets 
nest. . . " This statement was made over the mail received after 
the May column. He clarified his stance- he WAS NOT 
advocating that anyone with a CoCo change to an MS- 
DOS system, nor that MS-DOS was a substitute for OS- 
9. The point was that the new machines were not the ticket 
for anyone who wanted more out of their Color Com- 
puter. If one is looking for another computer, though, an 
MS-DOS machine- with its vast software base- might be a 
better choice than one of the new machines with little 
software support. The new machines were basically where 
the CoCo was when it first appeared on the market. The big 
difference was that most other affordable home computers 
were not in much better shape than the CoCo, and those that 
had much software weren't far ahead. Lonnie also stated that 
this may be the last Print#-2 column. He invited readers to 
give their opinions- use this space for a continued editorial, 
or more information? Sorry Lonnie... I will miss you 
(some), but I'd rather see more for my CoCo! 

The OS-9 Underground had a few changes (for the better!) 
in just the second issue! The magazine was noticeably 
thicker, this time sporting 50 pages wrapped in a fluorescent 
green cover. The colored covers did add a bit to the maga- 
zines overall appearance. On the title page of this second 
issue appears a little box exclaiming "Now incorporates 
68xxx Machines". Rather than fold, "The 68xxx Ma- 
chines" editor/publisher Jim DeStafeno decided that 
there was no need to fragment the OSK market with two 
magazines. A merger agreement was reached between 
68xxx Machines and OS-9 Underground whereby Under- 
ground would absorb the subscription base and writers of the 
former. Several columns were carried over also. A comple- 
mentary disk with program listings was first offered this 
month. The disk would be "published" on a quarterly basis, 
the first being available in mid-August, for $35 yearly or $ 10 
per issue. There were fourteen advertisers in this issue, 
notably Delmar, Peripheral Technologies (makers of Sys- 
tem IV kits and boards), and Frank Hogg Labs (TC70). The 
only OSK system missing is the MM/1 (IMS). The subscrip- 
tion rates stayed the same, but cover price increased to $3 
due to the increase in size. Gale Force picked up on the 
extra 6309 power by introducing NitrOS9. This was a set of 

page 30 Tandy's Little Wonder 

patches for OS-9 Level II that allowed native mode opera- 
tion of the Hitachi 6309, similar to the B&B PowerBoost. 

The August OS-9 Underground issue featured a communi- 
cations theme. An insert featuring many OS-9 supporting 
Bulletin Board Systems (BBS) was a nice touch. The cover 
color this month was fluorescent orange. A short Chicago 
CoCoFest report (to be continued next month) and a rather 
detailed review of several OS-9 BBS software packages 
was featured. Sixteen advertisers and 53 pages... not bad 
for only the third issue ! Keep up the good work, Allen ! A very 
interesting feature article instructed one on how to connect 
multiple terminals to a CoCo, creating a small LAN (local 
area network) with no extra software, just some cabling and 
serial port cards. 

The Hitachi 6309 and Burke&Burke's Powerboost made 
the headlines in the September Rainbow. Marty Good- 
man described the history of the 6309 and also reviewed 
the PowerBoost. We are told that the "new" 6309 (it had 
actually been around since 1987!) may also increase speed 
under Disk BASIC by as much as 15%, but the BASIC 
ROMs would have to be modified (or patched in RAM of a 
CoCo 3). Bill Vergona of Cer-Comp reported that he was 
95% complete on an assembler (m/1) that would take 
advantage of the 6309 under DiskBASIC. One would have 
to install a 6309 in order to utilize the assembler or any 
software written for it. Bill was also considering modify- 
ing some of his software for 6309 operation. JWT 
Enterprises had an interesting ad. "If you are interested in 
the latest, new products for the CoCo and the 'newer 
breed' of machines, write to us..." Just what do they have 
in mind here? Will have to send a post card and find out. The 
smaller size of OS-9 Underground meant less lead time (and 
overhead), and they were able to "get the jump" on Rainbow 
with the 6309 story. An issue of OS-9 Underground was 
missing this month, but the magazine was well represented 
at the October Atlanta CoCoFest. What gives Alan? 

JWT let on to what they were up to last month. October's 
Rainbow sported a full page ad for UpTime, an advertising 
newsletter covering all CoCo and 68xxx machines. Not 
a magazine, the newsletters' function was to provide low 
cost advertising and product info for the supported products. 
One year subscriptions were available for $15 in two install- 
ments of $7.50 each. Nine-Times OS-9 disk magazine was 
also continued. Burke&Burke introduced another new 
product- Thexder: OS-9. This OS-9 program took the code 
from the Tandy Thexder ROM pak and patched it for 
operation under OS-9, similar to the World Class Chess 
program introduced earlier. Gale Force advertised their 
NitrOS9 software this month. It was now available as a kit 
with a 63B09E and installation instructions. Missing 
this month was PRINT#-2. Seems a lot of readers, while 
appreciating the fact that Lonnie was keeping the Rainbow in 
publication, would rather have more info than 1/2 page of 
editorial. Alan Sheltra answered subscriber inquiries about 

the missing September OS-9 Underground with the news 
that a double issue would come out this month. The 
double issue was finally delivered in November! At the 
time this book went through final editing (March '93), 
the next issue was nowhere to be seen, and inquiries 
weren't being answered. It seems we have lost yet another 
support source. 

Although Lonnie Falk said he would not be covering the 
68xxx machines just a few months ago, it seems a truce had 
been called between the Rainbow and hard core OS-9 users. 
John Donaldson authored the first of a series of articles 
on his experiences with his new MM/1 in November. 
Mail from worried CoCo users had a lot to do with Lonnie 's 
first decision, mail from angered OS-9 users and even 
advertisers (the three producers of the 68xxx machines had 
pumped a LOT of money into Rainbow advertising !) prompted 
this repositioning. Cray Augsburg stated that although 
Rainbow wasn't going to put a lot into support of the new 
machines just yet, they would consider articles on them 
for pubUcation. 

A "C" programming language compiler had been avail- 
able for the Disk BASIC CoCo user in the early days, but had 
not been available for some time (last advertised in Dec . '84 
Rainbow). This prevented many users from learning that 
language as they had no interest in learning the intricacies of 
OS-9. Well, Infinitum Technology changed all that in 
December '92. They introduced a complete C compiler, 
assembler, library/linker, command coordinator, and 
text editor package for the CoCo 2 and CoCo 3 Called 
simply COCO-C, this was a complete C development pack- 
age based on the original Kernighan and Ritchie C 
standards (as was OS-9 C). 

A sad note for the CoCo community appeared in the Febru- 
ary '93 issue of UpTime. In their usual three page ad, 
CoCoPRO! printed a letter stating that they would soon 
cease operations as a CoCo vendor. An unusual offer was 
made: buy at least $30 of software from a discounted Ust 
of products that CoCoPRO! owned outright, and a 
Ucense to use ALL 14 of the listed products would be 
granted. The "catch" to the offer was that at least 33% of 
the mailing list had to take up on the offer. The programs 
could be obtained via a special password to a database on 
"Jim's CoCo Corner" BBS (313-292-4713), E-mail on 
Delphi, or by sending $1 per disk to and $3 shipping per 
order to the CoCoPRO! address. If 33% didn't respond, the 
programs wouldn't be released but one would still have the 
software one paid for. Not a bad deal ! The letter was also sent 
to many CoCo users via direct mail, bringing the total sent 
to 1966 plus the just under 300 UpTime subscribers 
(who weren't counted in the total). 84 were returned as 
undeliverable, leaving 1882 for the group. This meant 752 
would have to place orders for the offer to succeed. As of 
19 February, Dave reported that the original goal was 
unlikely to be met, so the response rate was lowered to 

22% and the deadline to 10 March. At that time, any who 
participated would be able to get copies of all the software 
for $ 1 per disk plus shipping, provided the lowered goal was 
met. CoCoPRO! granted licenses to the software to other 
vendors to guarantee continued availability. Even if the goal 
wasn't met, Dave promised "something extra" for those 
who supported him in the last days. Sorry to see you go 
Dave, but glad you made an effort to pass everything on 
rather than just leaving as so many others have! The offer 
ended up netting only 1 8% total response. 

Why did CoCoPRO! faU? The CoCo community is small, 
and naturally getting smaller. Dave Myers attempted to run 
CoCoPRO! as a full time business, while most other 
vendors run their businesses as part time or sideline endeav- 
ors. There simply is not enough business to keep a full 
time operation going and growing! Most vendors make a 
small amount from their efforts, but a lot of the energy is 
pure enjoyment and support of the CoCo. There isn't enough 
money in the CoCo community any more to support a 
thriving, full time operation. This shouldn't discourage us- 
ers from marketing their software, just don't expect to make 
a fortune in a shrinking, tight market. CoCoPRO ! did well 
their first couple years, and Dave must be applauded for 
his efforts and support of the CoCo community. 

Talk of a possible new magazine hit the FIDO network and 
Delphi in February. This new magazine would be supporting 
primarily Disk BASIC, but also CoCo OS-9 and limited OSK 
coverage. In May, the announcement came through that the 
magazine, "the world of 68' micros" (all in "micro" let- 
ters!), was a go! The first issue would be delivered in 
August... get those subscriptions in! 

Really sad news started trickling down in March. Falsoft 
started calling advertisers and letting them know that the 
May issue would be the last of "The Rainbow". The 

decission at Falsoft couldn't have been easy. "The Rainbow" 
made Falsoft into what it is today. From a business stand- 
point, however, "The Rainbow" couldn't continue. Subscrip- 
tions were down to a point that the publishing capacity could 
be put to better use printing almost anything else. That "The 
Rainbow" survived as long as it did was due to the good will 
of Lonnie Falk. Thanks Lonnie. . . you kept us all informed and 
helped us to learn one heck of a lot about Tandy's little 
wonder... much more than Tandy ever did! On a personal 
note, without "The Rainbow", this book would have beennext 
to impossible to write... 

What does the future hold for the CoCo? Who could have 
imagined that the CoCo, almost "ignored to death" by Tandy 
in the beginning, would be around today to enjoy its thir- 
teenth birthday? With continued support from YOU, the 
current users, the Color Computer will be around for at 
least another decade. It was with this in mind that this book 
was written... to keep your CoCo alive and well for many 
more years to come... 

Tandy's Little Wonder 

page 31 

CoCo Hardware Prices... 

The following prices were obtained from Radio Shack ad- 
vertisements and catalogs. This list is far from all inclusive 
(my personal RS catalog collection dates back to 1987), but 
does give an idea as to what early CoCo enthusiasts gave for 
their equipment. If an item is not priced for a given year, that 
usually means that earlier prices were carried over (no 
change). Note that CoCo specific items use 3xxx catalog 
numbers. These will be shown first, with remaining numbers 
in numerical order. Listed printers have the 4 pin CoCo style 
serial connector and all have 9 1/2" wide carriages and 9 pin 
print heads unless otherwise noted. 

1980- Introduction 





$399.00 - 4K CoCo 1 
$599.00 - 16K CoCo 1, Extended BASIC 
$24.95 - Joysticks (pair) 
$399.00 - TRS-80 Color Video Receiver 
(13" digitally tuned TV) 
$119.00 - 16K RAM Upgrade 
$99.00 - Extended Color BASIC Upgrade 
$59.95 - CCR-80A Cassette Recorder 




n/a - 32K CoCo 1 

n/a -I6KC0C0I 

$199.00 - 32K RAM Upgrade 

$4.95 - CoCo printer cable 

$399.00 - Line Printer VII 

$799.00 - Line Printer VIII 

$149.00 - TRS-80 Modem I (300 baud) 

$39.95 - Plug 'n Power Controller 

(original- uses cassette port) 

$1995.00- Multi-Pen Plotter (use w/ digitizer) 

$199.95 - CGP-115 (12 cps, 4.5", color) 

$449.00 - Screen Digitizer 

26-1196 - $349.95 - Color X-Pad 
26-1211 - $499.00 - Network 2 Controller 

(software/cables included) 
26-1212 - $599.00 - Network 3 Controller 

(software/cables extra) 
26-1253 - $399.00 - DMP-100 (50 cps) 
26-1254 - $799.00 - DMP-200 (120 cps) 
26-2775 - $149.00 - Network 3 Software (floppy drive) 



$199.00 - 64K CoCo (9/83) 

$119.95 - MC-10 Micro Color Computer 

$39.95 - Deluxe Joystick 

$499.00 - Disk Drive Kit 

$179.95 - Multi-Pak Interface 

$49.95 - Color Mouse 

$239.95 - 16K CoCo 2 

$319.95 - 16K CoCo 2, Extended BASIC 

$59.95 - CCR-81 Cassette Recorder 

$99.95 - TP-10 Thermal Printer (30 cps, 4") 

$699.00 - CGP-220 Ink Jet Printer (color) 

■ $159.95 - 16K CoCo 2 
$199.95 - 16K CoCo 2, Extended BASIC 

n/a - 16K CoCo 2 w/mono composite video 
adapter (factory installed, schools only) 

■ $119.95 - I6KC0C0 2 
$99.95 - 12/84 

- 16K CoCo 2, Extended BASIC 

- 64K CoCo 2, Extended BASIC 

- FD-500 Disk Drive Kit 
8/84 on 

Deluxe RS-232 Pak 
CCR-82 Cassette Recorder 

SPECIAL - $299.95 - 16K CoCo 2, CGP-115, CCR-82, 
Joysticks, Vocabulary Tutor Cassette (11/84-12/84) 








- $259.95 
$199.95 - 

- $399.95 
$349.95 - 

- $79.95 - 

- $49.95 - 


26-3008 - $19.95 - Joysticks 

26-3012 - $29.95 - Deluxe Joystick 

26-3015 - $29.95 - 16K Upgrade (from 4K) 

26-3016 - $24.95- CoCo 2 Keyboard (w/ CoCo 1 adapter) 

26-3017 - $59.95 - 64K Upgrade (from 16K) 

26-3018 - $39.95 - Extended BASIC Upgrade 

26-3134 - $119.95 - 16K CoCo 2 

$88.00 - 12/85 
26-3127 - $219.95 - 64K CoCo 2, Extended BASIC 

$159.95 - 12/85 
26-3129 - $349.95 - FD-500 Disk Drive Kit 

$199.95 - 12/85 
26-3143 - $99.95 - Orchestra 90 Stereo Music Pak 

$79.95 - 12/85 
26-3144 - $99.95 - Sound/Speech Pak 

$79.95 - 12/85 
26-1178 - $59.95 - DCM-3 Modem (300 baud) 
26-1185 -$59.95 - Graphics Touch Pad 
26-1261 - $99.95 - TP-10 Thermal Printer (30 cps, 4") 

$79.95 - 12/85 
26-1268 - $599.00 - CGP-220 Ink Jet Printer (color) 

page 32 

Tandy's Little Wonder 

1985 (continued) 


26-1275 - $299.00 - TRP-100 Themal Ribbon Printer 

(battery or AC powered) 
26-1276 - $199.95 - DMP-105 (80 cps) 
26-1277 - $899.00 - DMP-430 (180 cps, 15", 18 pin) 
26-1278 - $599.00 - DWP-220 (20 cps, 15") 
26-1280 - $349.95 - DMP-130 (100 cps) 
26-2226 - $79.95 - Deluxe RS-232 Pak 

$59.95 - 12/85 
26-2228 - $89.95 - DCM Modem Pak (300 baud) 




- $99.95 

- $199.95 
$99.95 - 

- $299.95 

- $179.95 

- $24.95 

- $129.95 

26-3124 - $99.95 - Multi-Pak Interface 

26-3127 - $199.95 - 64K CoCo 2, Extended BASIC 

08/86 on 


- FD-501 Disk Drive Kit 

- FD-501 Drive 1 Kit 

- Electronic Book 

- Hard Disk Interface 

(works only with OS-9, Tandy 10/15/35 MB drives) 
26-3215 - $299.95 - CM-8 RGB Monitor 

- 128K CoCo 3 

- 5 12K Upgrade 

- 10MB External Hard Disk 

- DMP-430 (180 cps, 15", 18 pin) 
DCM-6 Modem (300 baud) 

35MB External Hard Disk 






$59.95 - 







- $9.95 - Hi-Res Joystick Interface 

- $69.95 - OS-9 Level I 

- $79.95 - OS-9 Level II 

- $99.95 - OS-9 Level II Development System 

- $49.95 - Two button Mouse 

- $299.95 - FD-502 Disk Drive Kit 
$219.95 - 12/87 

- $179.95 - FD-502 Drive 1 Kit 

- $99.95 - Appliance/Light Controller (serial) 

- $79.95 - Ochestra 90 Stereo Music Pak 

- $79.95 - Sound/Speech Pak 

- $219.95 - 128K CoCo 3 
S199.95 - 09/87-11/87; $129.95 - 12/87 

$99.95 - Modemphone 100 (300 baud) 
$99.95 - DCM-7 Modem (300 baud) 
$399.95 - DWP-230 (20 cps) 

26-3018 - $14.95 - Extended BASIC Upgrade 
26-3133 - $299.95 - FD-502 Disk Drive Kit 

$199.95 - 12/88 
26-3334 - $199.95 - 128K CoCo 3 

$129.95 - 12/88 
26-1385 - $199.95 - DCM-212 Modem (300/1200 baud) 
26-1814 - $379.95 - DMP-132 (120 cps) 
26-2802 - $219.95 - DMP-106 (80 cps) 


26-2815 ■ 
26-2821 - 


■ $29.95 - Pistol Grip Joystick 
$39.95 - 512K Upgrade board (bare) 
$149.95 - 256K RAM Kit (2 required for 512K) 

(NOTE: This was during the first RAM shortage) 

- $379.95 - DMP-133 (160 cps) 

- $279.95 - DMP 107 (100 cps) 
$129.95 - Disto Super Controller 2 (no-halt) 





- $19.95 - Joysficks 
$9.95 -06/90 

- $29.95 - Pistol Grip Joystick 
$21.95 - 12/90 

- $49.95 - Two Button Mouse 
$24.95 -06/90 

- $299.95 - FD-502 Disk Drive Kit 

$199.95 - 12/90 

- $299.95 - CM-8 RGB Monitor 

$179.95 - 12/90 

- $199.95 - 128K CoCo 3 

$99.95 - 12/90 

- $59.95 - CCR-83 Cassette Recorder 

- $89.95 - DC Modem Pak (300 baud) 
$9.95 -06/90 

1991 - The Beginning of the End 

- $9.95 

- Hi-Res Joystick Interface 

$4.95 -1 


- $22.95 

- Deluxe Joystick 

$11.95 - 


- $299.95 

- FD-502 Disk Drive Kit 

$149.95 ■ 

- 02/91 

- $299.95 

- CM-8 RGB Monitor 

$149.95 ■ 

- 02/91 

- $199.95 

- 128K CoCo 3 

$99.95 - 


- $89.95 

- DC Modem Pak (300 baud) 

$9.95 -1 








The last appearance of the CoCo in a Tandy catalog was in 
RSC-22 ( 1 99 1 ). The last Tandy CoCo ad ran in the May 1991 
Rainbow. During late 1991 and all of 1992, many software 
packages were discounted nationwide. Users eagerly sought 
the OS-9 software, especially Level II, the Level II Develop- 
ment System, and the"'C" Compiler. Other software was 
deeply discounted, eventually being cleared out for as little 
as $1 ! Even today, a few game cartridges and, more rarely, 
disk software can be found in the back corner of Radio Shack 
stores. Some of the software will not show up on the stores' 
computer, meaning that the manager can just about name any 
price. Most cartridges will be found for $3.99 or less. The 
author recently picked up a copy of "DynaCalc" (OS-9) for 
just $1, so do look! 

Tandy's Little Wonder 

page 33 

CoCo Clones... 

an attempt to ride Tandy's wake.. 

There were only three CoCo clones ever made. The most 
known in the U.S. is the Dragon Systems Ltd. (a British 
company) "Dragon", imported to the U.S. by Tano. A 
second clone was advertised in Byte Magazine, the Sampo 
Color Computer (made in Korea), but never made it to the 
sales floor. It is quite possible that the ROMs used were near 
duplicates (if not blatantly so!) of the Tandy code, and that 
Tandy therefore prevented importation. Until four to five 
years ago, U.S. copyrights weren't protected in most Asian 
countries, including Japan and Korea. One could walk into a 
Korean computer store and find hundreds of copies of 
commercial software for share-ware prices... averaging $5 
per disk, plus $5-$10 for a manual. 

The third "clone" was not really a clone at all, but an attempt 
to make an improved but downwardly compatible computer. 
The FHL TC9 used a 68B09 and GIME just like the CoCo 
3, but had some improved hardware design. It was intended 
to primarily be an OS-9 platform. 

The Dragon Systems/Tano Dragon 

The following article was originally written for the October 
issue of Color Computer News by Alfredo Santos but 
never appeared due to the magazines discontinuance. 

Enter The Dragon/64 

Alfredo Santos September 30, 1983 

The Dragon/64 computer, which is enjoying great success 
in England, is now available in America. What makes the 
Dragon worthy of mention in this magazine is the fact that it 
uses a 6809E microprocessor and Microsoft BASIC just 
like our friend the TRS-80 Color Computer. 

When I first heard about the Dragon/64 (and little brother 
Dragon/32) my first question was: "Will Color Computer 
programs run on the Dragon?" . The answer is YES. . . and NO ! 
The incompatibility of BASIC word tokens between the 2 
machines prevent CoCo programs from working on the 
Dragon, but not to worry! If you save a CoCo program using 
the ASCII fomat (i.e. : CSAVE "filename",A) it will CLOAD 
and RUN on the Dragon with little or no problem. Problems 
may occur if any memory locations in low RAM are PEEKed 
or POKEd and problems will occur for sure if any CoCo 
ROM routines are called. 

Here's why: Dragons' Color BASIC and Extended Color 
BASIC are identical to CoCos' in many ways with some 
major exceptions. Both are burned into a single 
HN4827128G-30 28 pin EPROM. While the Dragons' 
BASIC chip (IC 1 8) occupies memory locations &H8000- 
&HBFFF like the CoCo, ROM entry points are different. 
CoCo's POLECAT routine, for instance, is at &HA1C1 
while on the Dragon it's at &HBBE5. This fact prevents 

Color Computer machine language programs from running 
on the Dragon unmodified. 

Dragon ROM entry points and CoCo BASIC equivalents: 
CoCo Dragon 

Address Address Comment 


(A002) A282 (A002) B54A CHAR OUT (cass) 

(A004)A77C (A004)8021 CASS READ 

(A006)A70B (A006)B93E BLOCK IN 
(A008)A7F4 (A008)B999 BLOCK OUT 
Both the CoCo and Dragon have indirect addresses at &HAOO0-&HAO0C- the 
Dragon's bid at CoCo compatibility. 

894C 9D3 

95CF A95D 



A02A B3B7 



A 176 B50A CHAR IN 

A186 B51A 

AlBl B538 


A282 B54A CHAR OUT (cass) 

A290 B560 

A2A8 B578 


A30A BCAB CHAR OUT (screen) 



A393 B5C9 

A398 B5CE 

A42D B663 

A444 B67A 

A46C B6A8 

A491 B6CD 

A502 A095 

A59A B7CC Data mover routine 

A5EE B820 

A6I9 B84B 

A629 B85B 

A635 B867 

A65C B88E 

A65F B891 

A663 B895 

A701 B933 


A77C BDE7 Cass. READ out 


A7D1 B480 

A7D3 B482 

A7D8 BE68 


A928 BA77 Clear Screen 

A95 1 BAAO 

A956 BAAS 

A974 BAC3 

A976 BAC5 sound routine 

A9DE BD52 

AD19 8417 Clear mem (NEW+3) 

B277 89B4 get operand 

B99C 90E5 PRINT text string 

page 34 

Tandy's Little Wonder 

Another area of major incompatibility is tlie keyboard (HI- 
TEK 107044 H). Although the Dragon has a fuU stroke 
keyboard, its matrix is not wired the same way as the CoCo 
keyboard. For example, a CoCo machine language program 
(which you've modified, of course) will produce unex- 
pected keyboard input. Typing the following: "DRAGON 
COLOR COMPUTER" will put this on the screen: "4B 1 7/. 3/ 
/& 3/-@ED5B". Indications supporting The keyboard ma- 
trix incompatibility is the fact that if the Dragon keyboard is 
installed in the CoCo, or vice versa, the weird output contin- 
ues. This condition does not affect any CoCo BASIC pro- 
grams running on the Dragon (unless you are PEEKing the 
keyboard rollover table to check keys pressed). 

A couple more items on keyboard related matters: Dragon 
basics' routine to poll for entry from the keyboard is 
somewhat less efficient than CoCo's. I'm not a speed typist 
but, in the two years I've been computing, I've gotten pretty 
proficient at typing the word "LIST". The word is typed so fast 
that before the "L" key is released, the "I" key is being pressed 
then "S" and "T". The Dragon turns my lightning "LIST" into 
"LST". This occurs because the Dragons' keyboard polling 
routine will not recognize the "I" key stroke until the "L" key 
is released because they are apparently on the same row of 
the keyboard matrix. This also effects the method used to 
pause scrolling during a LIST with a "SHIFT@ ". The inability 
to accept a double keystroke happens only while Dragon is 
in the 32K mode (on power-up). While in the 64K mode, not 
only is the problem eliminated but, if a key is held down for 
more than a few tenths of a second, it starts repeating. 

By the way, you'll know ataglancewhetheryou're in the32K 
or 64K mode simply by the cursor color. In the 32K mode, 
the cursor will be a blinking solid black graphics character 
while a blinking solid blue cursor indicates 64K mode. 

Dragons' 64K mode is entered by typing "EXEC" and press- 
ing ENTER. Easy hey?? When the machine is turned on, part 
of its initialization process includes moving data into low 
RAM (&H0000-&H03FF) for the BASIC interpreters to 
use. For instance, the system uses location &H009D to hold 
the EXEC address of the last machine language which was 
loaded into the computer. This eliminates having to specify 
an EXECution address after you CLOADM a program. 
Power-up initialization puts the value &HBF49 at &H009D 
Dragons' 64K mode ROM entry point is &HBF49. If you 
wish to enter the 64K mode AFTER having loaded in a 
machine language program, &H(X)9D will then contain then 
EXEC address of that program so typing EXEC &HBF49 
will be required to access the 64K. Another nice thing about 
the Dragons' use of its 64K is that it frees user RAM from 
&H0600-&HBFFF's by moving the ROMs up to &HC000- 
&HFFF0. The CoCo doesn't move its ROMs, so you end up 
with 2 blocks of RAM (&H0600-&H7FFF and &HC0OO- 
&HFFFO, with memory locations &HA000-&HBFFF; 
&H8000-&HBFFF for Extended BASIC CoCos) off Umits 
because CoCo's ROMS are there. 

With 64K of RAM (Dragon/64), full stroke keyboard, 
parallel printer, port and color composite monitor output, 
this computer should be a very serious consideration for 
anyone in the market for an inexpensive yet powerful ma- 
chine with high resolution graphics capabilities. In addition 
to the above mentioned ports, the Dragon has the standard 
CoCo type connections for 2 joysticks, a cassette recorder, 
40 pin ROM cartridge/expansion slot, and TV hook up. The 
power transformer is externally mounted, making the com- 
puter run a good bit cooler than a CoCo... no fan needed! 

The Dragon has all the power and versatility of the very 
popular TRS-80 Color Computer plus features which make 
the Dragon a more professional machine with greater capa- 
bilities. If you've held off buying the TRS-80 Color Com- 
puter because of some above mentioned limitation then now 
is the time to stop "Dragon" your feet and check out this very 
"great Briton" (You liked the Beatles, didn't you?). 

Even today, there is continued suppcMt for the Dragon in the 
United Kingdom (England). There is an active user group 
that continues to sponsOT national shows similar to the 
CoCoFest in the U.S. If the Dragon can survive this long 
surely the CoCo can! 

The last known information on the Dragon indicated that 
EUROHARD attempted to revive it as an educational com- 
puter. New-in-the-box Dragons are still available from Cali- 
fornia Digital (17700 Figueroa Street, Gardena, CA 90248; 
phone 800-421-5041 (orders) or 310-217-1945 (tech sup- 
port/information).The current address for the user group is: 
National Dragon User Group, c/o Paul Grade, 6 Navarino 
Road, Worthing, Sussex, U.K. "the world of 68" micros" 
magazine will feature some information on the Dragon from 
the British user group in the future. 

.^California Digital, Inc: 
■^ITTOO Figueroa Street 
'- Gardena, CA 902481 


FAX (310)217-195l| 

Some items are limited inverTtory.'C 
and sut^ect to avadabte stodc- ; ' * V 

Dragon Computer 

A knock off of the Radio Shack Color Com- 
puter. Ideal low cost computer for getting the 
kids away from yours. The Tano Dragon was 
manufactured under the license of the British 
Broadcasting Company. Complete with 
printer and serial port. The computer 
outputs composite col6r video and R . F. 
Will operate on with your television. 
Supplied with Basic, Data Manager 
and Word processing package. 

Summer • 1992 

Tandy's Little Wonder 

page 35 

Tomcat TC9... Frank Hogg Labrotories bid to build a better CoCo. 

FHL intnxluced the Tomcat TC9 in June of 1990. Unlike 
other 0S-9/0SK computers, the TC9 was designed to use 
existing CoCo hard and software, reducing the initial invest- 
ment required. To maintain this compatibility, it used a 
68B09E and original Tandy GIME chip. A CoCo type 40 pin 
expansion bus was also included via a 40 pin header connec- 
tor. A one or two 40 pin card edge connector ribbon cable 
attached to the header. Even the MPI could be attached! 
Since the bus was fully buffered (unlike the CoCo's), the 
cable presented no problems, and a cable with a couple more 
connectors would probably work just as well as long as it was 
kept to a minimal length. A 68xxx type "K-bus" was also used 
on the TC9. This allowed adding numerous FHL K-bus cards 
and even a 68xxx processor card. The processor card could 
be used as a coprocessor for 6809 OS-9 or vice-versa. A 
special lOMHz 68000 based card, the Tiger, was designed 
specifically for that purpose, though one of the faster, more 
expensive 68xxx based cards (such as the 15MHz 68070 
based TC70) could also be used. 

Features of the TC9 included: 

* CoCo 3 soft/hard ware compatible (OS-9) 

* 25% faster than the CoCo 3 

* IBM/PC compatible 101 key keyboard, case, and power 

* Two hardware serial ports- no need for RS-232 Paks 

* Support for a PC type serial mouse 

* Parallel printer port 

* Improved joystick ports, higher resolution 

* Better sound capabilities 

* CoCo 3 and K-bus expansion capabilities 

* Up to 1MB of DRAM on the motherboard (the original 
design used a CoCo 5 12K upgrade and Disto 1MB board, the 
final used four 256K SIMMs and a plug in control, or DAT, 

The TC9 was designed with running Tandy/Microsoft/Mi- 
croware Super Extended Disk BASIC (CoCo 3 BASIC) in 
mind. There were some problems, however. The first was 
that Tandy held the copyright, so an agreement would have to 
be reached with or ROMs purchased directly from them. 
Second was the improved hardware. OS-9 could easily cope 
with the added hardware by supplying the correct software 
drivers. Disk BASIC was another story- the code itself 
required modification. 

FHL eventually got around most of this, though it took about 
a year of tinkering. The first step was hardware. An emulator 
circuit was devised that would intercept CoCo output and 
send it to the correct TC9 pwrt. Since the TC9 was a bit faster 
than the CoCo 3, the hardware didn't slow operation when 
compared to the original. Rather than deal directly with the 
ROM situation, software was supplied that would allow a 
CoCo 3 owner to copy his ROMs to disk then patch them for 

TC9 opCTation. This was used since relatively few TC9 
customers insisted on Disk BASIC support- most wanted to 
run OS-9 only. This method sort of stepped around copyright 
infringement, since one was expected to own a CoCo 3. 

Unfortunately, the improvements just weren't enough for 
most OS-9 users who had outgrown their CoCo 3s, and the 
price was a bit high for those just seeking a CoCo 2 or 3 
replacement. Prices started at $499.95 for a starter system 
which included a low profile case, and 512K (1990 price. 
The second type sold for $549.95, but used a mini tower 
case, a $20 option for the 1990 unit). One still needed their 
CoCo disk drive controller and drive, CM-8 (or similar 
RGB A) or composite monitor (no TV ouq^ut), and a PC/AT 
style keyboard (PC/XT keyboard not supported). 512K 
CoCo 3s could still be purchased new for under $350 in 
1990. Note that if one purchased the 512K upgrade and 
RAM bom Tandy, the total price would have been $539.80. 
Tandy was still stuck with lots of 256K DRAM chips they 
were forced to purchase during the 1989 DRAM shortage, 
and were STILL trying to pass the high cost to the end user. 
Most purchased the bare board ($39.95) and got their DRAM 
elsewhere, or purchased third party upgrades for $150 or 
less. In 1991, a complete TC9 system with one 360K floppy, 
keyboard, 20MB hard drive, 1MB upgrade, and Magnavox 
1CM135 monitor was priced at $1649.95. Boards could be 
purchased by those wishing to assemble their own TC9 
(main board set- $349.95, 1MB upgrade board- $59.95... 
memory not included). 

The TC9 faded into oblivion after only two years of produc- 
tion. Frank Hogg stated: "The TC9 took far longer to finish 
than any previous computer I've done because of the com- 
plexity of marrying a 8 bit CoCo to a 16 bit 68000. We went 
through 4 design stages. Tliis work was done by Bob Puppo 
with the help of just about everybody in the CoCo commu- 
nity offering advice." To bad all that work didn't bear more 
fruit, as the TC9 was truly the closest thing ever to "the CoCo 
4 Tandy should have built"! 

Since 1976 

204 Windemere Road 

Syracuse, NY 13205 

FAX 31 5/469-8537 

Call 315/469-7364 

page 36 

Tandy's Little Wonder 

Operating Environments and Programming Languages. 

Color BASIC 

The authors first thought was to make separate sections 
dealing with these two subjects. This wouldn't really be 
appropriate for the CoCo though. It's main operating envi- 
ronment, Color BASIC, is also a programming language! 

Like many of the first generation of "home" computers, the 
CoCo is ready to go as soon as it is turned on. All of these 
computers (Timex/Sinclair ZX & TS series. Commodore 
VIC-20, 16, & 64, Atari 400 & 800, CoUeco Adam, TI 99/ 
4A, etc.... even the IBM PCjr) have a BASIC programming 
language stored in a ROM chip. The ROM is active after 
power is turned on, meaning that nothing has to be loaded 
before beginning to operate the computer (unless working 
with a pre-recorded program). This was done to make the 
computers seem less intimidating. Cartridge slots were also 
a part of most early home computers. A cartridge containing 
a different ROM chip (Tandy ROM-Pak) could be inserted 
before turning the system on, and when powered up whatever 
was in the cartridge ROM would be ready to go. What could 
be simpler? 

There are four types of BASIC for the CoCo in three 
versions: Color BASIC, Extended Color BASIC, Disk 
BASIC and Super Extended Color BASIC. Color BASIC 

is the simplest form of BASIC for the CoCo. It came in an 8K 
ROM and was the first BASIC available. There were no 
definition commands (DEFUSR, DBF FN, etc.), only one 
trigonometric function (SINe), no error trapping, and few 
graphics commands (only POINT, SET, and RESET). If a line 
was typed in wrong, it would have to be retyped- there was no 
editing capability. This BASIC was very similar to TRS-80 
Model I Level I BASIC. CoCos with only this BASIC in- 
stalled would display "COLOR BASIC VERSION 1.0" on 
screen when turned on. 

It didn't take Tandy long to realize that programmers wanted 
more. Extended Color BASIC (ECB, similar to TRS-80 
Model I Level II) was announced when the CoCo was intro- 
duced in September 1980, with an expected introduction of 
"late November". It actually arrived in mid January, 1981. 
Extended BASIC contained many new commands in another 
8K ROM that plugged into a socket next to the existing 
Color BASIC ROM, for a combined total of 16K. New 
commands included those "missing" from Color BASIC, 
including a wide range of graphics commands, algebraic and 
trigonometric functions, the play command, and many new 
programming statements- the most notable being a state- 
ment to save machine language programs on tape. The 
Extended ROM could be added to any CoCo for $99.00 plus 
installation. Many of the graphics commands required 16K 
to use (the first CoCo was only 4K), the upgrade would add 
an additional $119.00 (plus installation) to the price. The 
best deal was to purchase a 16K Extended CoCo new- it was 

only $100 more than a 4K non-Extended model ($599 vs. 

There were some minor problems in Color BASIC 1.0. One 
was the printer driver. Tandy used a seven bit code to drive a 
printer in the CoCo. Less than a year after the CoCo's 
introduction, printers (including Tandy models) standard- 
ized on an eight bit code. Tandy first rectified this by 
supplying a new printer eight bit printer driver on tape for 
free (note that some early Tandy printers were seven bit 
input, others were switchable between seven and eight bits). 
This was brought on by the introduction of the Line Printer 
VII, the first with a built-in CoCo serial connector (four pin) 
and the first capable of dot addressable graphics. The seven 
bit printer driver would print characters but no graphics. 

In November 1981, the new 32K CoCo was introduced. 
With it came a new revision of Color BASIC- version 1.1. 
The main reason BASIC was changed was the 32K RAM 
upgrade itself The old 1 .0 ROM would only address up to 
16K, so it had to be changed. While the engineers were 
making changes anyway, they decided to add some items to 
the original ROM code and to fix a couple minor problems, 
though the official stance was that nothing was wrong with 
the 1.0 ROM. The additions included 32K support, the eight 
bit printer driver, and displaying an "S" while searching a 
cassette for a file and an "F" when a file was found. 

When disk drives became available from Radio Shack in 
October of 1981, a new BASIC extension came with them. 
Rather than create a disk based operating system, Tandy 
decided to add commands to BASIC that would allow access 
to the disk drives. Disk Extended Color BASIC (DECB) 
resided in an 8K ROM contained in the disk controller. With 
the controller plugged in the disk commands loaded into the 
Program-Pak area of Color BASIC. This method allowed the 
CoCo to retain simplicity of use with the speed and conve- 
nience of a disk drive. An advantage to BASIC programmers 
is immediate access to disk information. A true disk loaded 
disk operating system (DOS) not only has to have BASIC 
loaded from disk, but BASIC has to call the DOS to access 
most disk information. DECB has commands that allow 
extensive disk data manipulation, including directly reading 
and writing to specifiable portions of the disk. 

A new type of CoCo 2, the Korean made "A" and "B" models 
(and "A" or "B" follows the catalog number) required the last 
revision of Color BASIC- version 1.3. These computers 
used a different type RAM chip, the 4464, and required 
different timing rates than previous DRAMs. A new SAM 
(74LS285) also had to be used. The new SAM supported the 
256 cycle RAM refresh rate required by the 4464 chips as 
well as the 128 cycle refresh of the old style chips, so it 

Tandy's Little Wonder 

page 37 

could be used in any CoCo but the original SAM could not. 
All the 1.3 ROM does is tell the SAM to use the 256 cycle 
refresh rate if jumpers are set for the 4464 chips and change 
the revision number. Color BASIC and ECB are both burned 
into a single 28 pin, 128K ROM on these CoCo 2 models. 
Standard Color BASIC ROMs will fit, but won't work with 
44xx series RAM chips. The 1.3 ROM will also work in 
earlier CoCos. 

The final type. Super Extended Color BASIC, was intro- 
duced in 1986 with the CoCo 3. Like Disk BASIC, this was 
an extension of the existing Extended Color BASIC. Due to 
the copyright agreement with Microsoft, Tandy couldn't 
alter the ECB code, and didn't want to pay high royalties for 
Microsoft to make the necessary changes... MicroSoft was 
much bigger now than they had been when Color and Ex- 
tended Color BASICS were written! 

In order to add commands to the CoCo 3, a new ROM was 
made for Tandy by Microware, publishers of OS-9. What 
happens is that the CoCo 3 powers up in an "all RAM" mode 
(ROM contents copied to RAM) and the new ROM patches 
the ECB code in RAM, much as one would alter the code with 
POKE statements, avoiding copyright problems with Mi- 
crosoft. Twenty six new commands were added to take 
advantage of the CoCo 3s enhanced graphics, text, and 
memory capabilities as well as error handling. 

The three people who designed the code also did something 
else with some extra space in the single 32K ROM (Color 
and Extended BASIC are in the lower 16K with minor 
changes, CoCo 3 BASIC in the upper)- they put a portrait of 
themselves ! To see them, hold down the CTRL and ALT keys 
while pressing the RESET button on the back of the com- 
puter. This does a "cold start" also, the RAM is reset and in 
most cases the computer behaves as if it has been turned off 
then back on, which is the only way to "cold start" a CoCo 1 
or 2 (pause at least 15 seconds before turning back on!). 
There are times when this may have to be done with a CoCo 
3 also, such as after running some machine language pro- 
grams. To return the CoCo 3 screen to normal and complete 
the "cold start", press RESET once more (holding no keys 
down this time). 

Note what the screen says when a CoCo 3 is powered up. It 
should read "Extended Color BASIC 2. 1 " or "Disk Extended 
Color BASIC 2.1" (or 2.0, depending on version in disk 
controller). No, there isn't really a third and fourth version 
of BASIC, nor a new version of Disk BASIC. The ECB code 
was changed to replace the " 1 " with a "2" to indicate a CoCo 
3. No new commands were added to Disk BASIC. It would 
have been nice had Tandy taken the opportunity to support at 
least 40 track drives, possibly even double sided. The most 
likely reason this support was not added was to maintain 
optimum compatibility with existing systems. 

Easy DECB Enhancements... 

There is an easy way to add a few extra to Color BASIC and 
DECB. Changes can be made to the system by poking 
different values into specific memory locations. This can be 
done easiest on a CoCo 3 as the ROM code is copied into 
RAM automatically. The CoCo 1 and 2 require being put into 
an all RAM operating mode (ROMs copied to RAM) by 
running the following program: 



30 CLEAR 999 

40 DATA 26,80,190,128,0,183,255,222,166,128 

50 DATA 183,255,223,167,31,140,224,0,37,241,57 

60 FOR 1=1 TO 21 :READ A:A$=A$+CHR$(A):NEXT I 

70 P=VARPTR(A$)+1 

80 POKE P,126 

90 EXEC P 


Note that unless the changes are made permanent by burning 
into an EPROM, they will be lost upon reset or power off . 

The first thing one may want from the CoCo is more speed. 
There is a relatively simple way to accomplish this. . . through 
a POKE! Type POKE 65495,0 to put a CoCo 1 or 2 into 
"double speed" mode. What this does is address the ROM at 
twice the normal clock speed (1.79MHz instead of .89MHz) 
of the CPU. POKE 65494,0 returns the processor to normal 
speed. Another address (POKE 65497,0) addresses the 
ROM and RAM at double speed, but terminates RAM re- 
fresh (could cause loss of memory) and also makes the 
screen unreadable as it affects the video clock rate also 
(which won't operate at double clock speed). If one has lots 
of math functions to process, this may come in handy, but 
the slow down POKE (65496,0) will have to be entered to 
view the results. The computer could also lock up if the 
RAM drops any bits. This seems to work in practice, as the 
author has turned the TV off and let CoCo plot away at 
Mendlebrot graphics all night (the particular program re- 
quired approximately six hours to plot a single graph at 
double speed), but it is not recommended programming 
practice and would be unacceptable in a commercial pro- 

Some CoCo 1 models required the following minor changes 
to allow proper double speed (65495,0) operation: 

D & E board - clip capacitors C30, C73, & C75 (also C85 

when using a disk controller) 

F or NC board - clip capacitors C36, C37, and C86 

page 38 

The board letter is in the serial number printed on the 
booard. No harm will come from removing these 56pf 
capacitors, they are for filtering and distort the clock signal 
in double speed mode (there may be a slight increase in RFI, 
but it shouldn't be noticeable). 

Tandy's Little Wonder 

The CoCo 3 DOES NOT support the first "double speed" 
POKE. Tandy actual did something better... they decided to 
support the double speed POKE fully ! The address at 65497,0 
supports true double speed operation of ROM, RAM (RAM 
is refreshed properly), and video. POKE 65496,0 still re- 
turns to standard speed. Many CoCo 3 programs take advan- 
tage of the double speed mode, but disk operation is still 
hindered because the Disk BASIC extension was not modi- 
fied. OS-9 Level II runs in double speed all the time- there 
is no way to slow the processor down! 

The following program makes several changes to Disk 
BASIC. These changes can be burned into an Intel 2764 
ROM to make them permanent. The 2764 is a 28 pin chip, 
meaning an adapter (available from Spectro Systems) is 
required for all Tandy controllers except the short one. 
Simply run the program and then save a copy of the Disk 
BASIC ROM code to disk (or tape). The listing is com- 
mented with explanations between program lines (don't type 
in the explanations, program lines are in bold). Eliminate 
the lines with unwanted features. Programmers may use 
portions of this listing in commercial products as long as the 
statement "Portions by F.G. Swygert & L.Todd Knudsen" is 
included in the new BASIC code. 

10 REM Program for setting printer baud, drive step rate, and 
double speed disli access, CoCo 3. 

Program was written for a CoCo 3. Will run on a CoCo 1/ 2 after 

changing all LOCATE statements to PRINT@ and running the ROM 

into RAM program. 

30 REM by F.G. Swygert, January, 1993 - 1110-1140 by L.Todd 

Knudsen, 1992 

60 POKE 65497,0 

CoCo 3 double speed; 65495,0 for CoCo 1/2 

65 POKE 150,18 

Change printerbaudrate to 1200. Will be2400(doublethevalue)with 

the speed-up POKE. 

70 IF PEEK(&HA282)=23 THEN 120 

Check for ADOS & EADOS3. ADOS should already be setup with 

faster drive access rates. If present go to line 120. 

80 IF PEEK(&HC004)=215 THEN 100 

Check if DECB 1.0/1.1. If PEEK value is 215, then DECB 1.1 is 

present. Value would be 214 for 1.0. If 1.1, go to line 100. If not 

(therefore 1 .0), continue. 

90 POKE &HD6CD,0 : POKE &HD723,20 : GOTO 140 

Set drive to 6ms access time, DECB 1 .0/2.0 

100 POKE &HD7C0,0 :POKE &HD816,20 : GOTO 140 

Set drive to 6ms access time, DECB 1.1/2.1 

120 CLS : SOUND 150,4 : LOCATE 14,16 : PRINT "Currently 

set up for 2400 baud printer." : LOCATE 14,17 : INPUT "Do 

you wish to change this? (Y/N)"; A$ 

Clear the screen : Make a sound with tone 150 for a duration of 4 : 

move cursor to column 14, line 16 : PRINT statement in quotes : move 

cursor to column 14, line 17: accept INPUT after printing statement 

in quotes, the INPUT will be stored as A string 

130 IF A$="y" OR A$="Y" THEN 320 : IF A$="n" OR 

A$="N" THEN 420 : GOTO 120 

If A string is "y" or " Y" (yes) go to line 320, if it is "n" or "N" (no) go 

to line 420. IfA string is neither, the computerwillgothisfar andstart 

over by returning to line 120. 

140 CLS : SOUND 150,4 : LOCATE 14,16 : PRINT"Currently 
set up for 2400 baud printer and 6nis drive" 

See comments for line 120. 

150 LOCATE 14,17 : INPUT "step rate. Do you wish to change 

this? (Y/N)"; A$ 

See comments for line 120. 

160 IF A$="y" OR A$="Y" THEN 190 : IF A$="n" OR 

A$="N" THEN 440 : GOTO 150 

See comments for line 1 30 

190 CLS : LOCATE 6,4 : PRINT" Select Drive Step Rate: " 


See comments for line 120. The PRINT at the end causes a blank line 

to be put on the screen. 

200PRINTTAB(8)"l=6nis 2 = 12ms 3 = 20ms 4 = 


PRINT the following beginning 8 spaces over. 

210 PRINT : LOCATE 6,8 : INPUT "Selected Value"; D$ 

See comments for line 120. 

220 IF PEEK(&HC004)=215 THEN 230 ELSE 270 

Check for DECB 1.1. If present go to line 230, otherwise go to line 270. 

230 IF D$="l" THEN POKE &HD7C0,0 : POKE &HD816,20 

: GOTO320 

240 IF D$="2" THEN POKE &HD7C0,0 : POKE &HD816,21 

: GOTO320 

250 IF D$="3" THEN POKE &HD7C0,0 : POKE &HD816,22 

: GOTO320 

260 IF D$="4" THEN POKE &HD7C0,0 : POKE &HD816,23 

: GOTO320 

265 POKE &HD762,2 

POKE the values for the specified step rate, DECB 1.1 thengotoline 

320 (see line 200 for rates). Line 265 sets the number of times the 

computer will try to read a disk before issuing an "I/O ERROR" (in this 

case, 2 tries- nonnally 5) 

270 IF D$="l" THEN POKE &HD6CD,0 : POKE &HD723,20 

: GOTO320 

280 IF D$="2" THEN POKE &HD6CD,0 : POKE &HD723,21 

: GOTO320 

290 IF D$="3" THEN POKE &HD6CD,0 : POKE &HD723,22 

: GOTO320 

300 IF D$="4" THEN POKE &HD6CD,0 : POKE &HD723,23 

: GOTO320 

305 POKE &HD66F,2 

Same as 230-265, except for DECB 1 .0. 

310 GOTO 190 

If none of the above, go back to line 1 90 . 

320 LOCATE 6,10 : PRINT "Select Printer Baud Rate:" : 


See comments for line 190. 

330 PRINTTAB(8) "1=600 2 = 1200 3 = 2400 4 = 4800 

5 = 9600" 

See comments for line 200 

340 LOCATE 8,14 : A=PEEK(65314) : B=INT(A/2) : C=A/2 



Move cursor to column 8 line 14 : the next four statements 

checktheprinterportforactivity : PRINT whether the printer is on or 


350 PRINT:LOCATE 6,18:INPUT"Selected Value"; R$ 

See comments for line 120. 

360 IF R$="l" THEN POKE 150,180 : GOTO 420 

370 IF R$="2" THEN POKE 150,87 : GOTO 420 

380 IF R$="3" THEN POKE 150,41 : GOTO 420 

390 IF R$="4" THEN POKE 150,18 : GOTO 420 

Tandy's Little Wonder 

page 39 

400 IF R$="5" THEN POKE 150,4 : GOTO 420 
410 GOTO 320 

POKE the values for the specified baudrate then go to hne 420. Note 
that the value is actually HALF the specified rate because the double 
speed POKE is used. 

This line allows a chance to stop if a mistake was made. EXEC 445 39 
makes the computer wait fora key tobepressed before continuing the 

430 IF PEEK(&HA282)=23 THEN 1000 
Check for ADOS/EADOS. If present, go to line 1000 
440 IF PEEK(&HC004)=214 THEN A$="C0EED52AD6 
D1D6F1D727D75E" ELSE A$="C101D617D7C4D7E4D 

Check for DECB 1 .0, use first string for data if it is present, else use 
the second string for DECB 1 . 1 
450 FOR V=1T024 STEP 4 
460 A=VAL("&H"+MID$(A$,V,4)) 

470 POKE A,189 : POKE A+1,240 : POKE A+2,157 : POKE 
480 NEXT 

490 POKE &HF09D,52 : POKE &HF09E,127 
500 POKE &HF09F,53 : POKE &HF0A0,255 
Lines 450-500 use the data strings in line 440 to POKE values into Disk 
BASIC to change timing so that double speed can be used reliably. 
510 IF PEEK(&HC004)=214 THEN 520 ELSE 600 
Check for DECB 1.0, go to 600 if not present. 
520 POKE 50952,78 
530 POKE 50986,84 : POKE 51083,78 
540 POKE 51104,78 : POKE 51135,78 : POKE 52300,78 
550 POKE 52697,78 
560 POKE 53680,40 
570 POKE 54111,78 
580 POKE 54342,39 
590 POKE 54642,40 : POKE 54677,40 
Lines 520-590 patch the following in DECB 1 .0 for 40 track 
operation (line by hne): KILL, FAT (File Allocation Table), 
GAT (Granule Allocation Table), FREE, BACKUP, COPY, 
DSKI$/DSKO$, and DSKINI. Values 40 and 39 are tracks, 
78 is the maximum number of files (68 for 35 tracks). 
600 POKE 50997,78 
610 POKE 51034,84 : POKE 51131,78 
620 POKE 51183,78 : POKE 51152,78 : POKE 52518,78 
630 POKE 52917,78 
640 POKE 53917,40 
650 POKE 54349,78 
660 POKE 54580,39 
670 POKE 54879,40 

See comments for lines 520-590, these for DECB 1.1. 
Clear screen, print three blank lines then FINISHED! 

MisceUaneous Useful PEEKs, POKEs & EXECs: 

1. POKE 111,254 : DIR - Prints disk directory on printer. 

2. POKE 308,0 : POKE 313,0 - Disables ALL disk com- 

3. POKE 308,19 : POKE 313,6 - Restores all disk com- 
mands (DECB 1.0; change 19 to 20 for DECB 1.1). 

4. POKE 113,0 : EXEC 40999 - does a "cold start". Can use 
POKE then press RESET (good for program protection- 
prevents listing after RESET). Mostly used for CoCo 1/2, 
CoCo 3 has CTRL-ALT-RESET (use EXEC 35867 with 
POKE 113,0 force 3). 

5. POKE 234,0 : EXEC 55135 - "parks" disk drive heads. 

6. PRINT PEEK(188) - Prints 14 with a disk system, 6 with 

7. POKE 282,0 - Sets lowercase display. 

8. POKE 282,255 - Sets uppercase display. 

9. POKE 293,0 - Disables all BASIC functions, 293,20 

10. POKE 306,178 : POKE 307,119 - Disables Extended 
and Disk BASIC only, 306,129 : 307,104 restores. 

11. PRINT PEEK(33021) - Prints 50 if CoCo 3. 

12. POKE 65281,0 - Locks out keyboard, RESET to re- 
store. POKE 65281,4 restores keyboard in a program. 

14. POKE 383,158 - Prevents listing of a BASIC program. 
POKE 383,126 restores. 

15. POKE $H167,&H39 : POKE &HFF22,21 - Enables 
CoCo 2B lowercase display mode, prevents ASCII saves. 
Try without first POKE. . . may not prevent ASCII saves then. 

16. PRINT PEEK(341) - ALT key (prints 191 pressed); 
PEEK(342) - CTRL key; PEEK(343) - Fl; PEEK(344) - F2 
(these will work on keyboards with four function keys also) 

17. POKE 65502,0 - Disables all CoCo 3 commands, reads 
only ECB portion of ROM directly from ROM, just as a 
CoCo 1/2 would. Some programs that won't run on a CoCo 
3 might after this. POKE 65503,0 restores normal CoCo 3 

More POKE enhancements can be found in the books "500 
POKES, PEEKS, 'N EXECS", "Supplement to POKES, 
for the CoCo III" series of books from Zebra Systems. These 
have many programming hints for all CoCos and are highly 
recommended to all programmers. 

page 40 

Tandy's Little Wonder 


Arts ' Disk Operating System,,, by Art Flexser 

A crucial step in the development of ADOS occurred in 
1983 when I decided to buy a Lowerkit for my CoCo 1 from 
Dennis Kitsz's Green Mountain Micro. I did this mainly to 
have lowercase available for telecommunicating, which I 
was doing quite a lot of on CompuServe's CoCo SIG. My 
preferred terminal program at the time was Colorcom/E. It 
was able to use a software-generated upper/lowercase dis- 
play on the PMODE graphics screen, but output to that was 
a bit sluggish for my tastes. In order to have lowercase on 
the regular 32 column hardware display, I needed one of 
Kitsz's gizmos, so off went my check in the mail. 

But soon, it began to bother me that whenever I would type 
a BASIC command in lowercase, all I got for my trouble was 
the familiar ?SN ERROR. I wrote a little ML patch for 
BASIC to make it understand lowercase commands. This 
exercise was intellectually satisfying to some degree, but 
was not of much practical value to me; LOADMing it was 
more bother than just switching to uppercase. 

Meanwhile, on CompuServe, I had run across a bunch of 
small utilities by various people to remedy assorted short- 
comings of the CoCo's stock BASIC. There were patches 
for automatic line-numbering , 40 tracks, fast step rates, and 
a few others, including a particularly nice one for editing the 
last direct-mode command, contributed by Bill Dickhaus, 
who later gave permission for me to use it in ADOS. After 
the 64K upgrade became available, several people on the 
CompuServe SIG put a number of these patches into a 64K 
program called DOS64.CC. I contributed my lowercase 
patch and a RUNM command. But even having a number of 
extra features collected into one utihty struck me as limited 
in usefulness; it was a bother having to boot up the utility and 
there was quite a bit of software that DOS64.CC was incom- 
patible with. It seemed to me that a collection of BASIC 
enhancements would be a great deal more useful if they 
were burned into an EPROM; this would not only avoid the 
hassle of having to boot it up from disk, but would also 
enable a much greater degree of software compatibility. I 
was also aware that Tandy had left 2K of free space in the 8K 
chip that Disk BASIC resided in; this free space would be 
ideal for a collection of enhancements to BASIC. 

I do not want to claim that the idea of putting enhancements 
into the Disk BASIC chip originated with me. There was a 
recently-developed product known as JDOS on the market 
from J&M Systems that had many of the same features I was 
thinking about putting into an EPROM. But JDOS had the 
important drawback of being incompatible with quite a lot of 
software. This was not really the fault of the authors, who 
were hampered by copyright restrictions in a way that I 
(debatably) was not. The folks at J&M had developed JDOS 
as an adjunct to the disk controllers they were selling. For 
them to have put a patched version of Tandy's ROM in their 

controllers would have been a copyright infringement, so 
they were forced to do a complete rewrite offandys' ROM. 
This changed the addresses of all the entry points into various 
ROM routines, resulting in a lot of incompatibility. Had 
Tandy included a full set of documented entry points in Disk 
BASIC, rather than just DSKCON, JDOS would have been 
much more highly compatible, and it is conceivable that I 
never would have bothered to develop ADOS. 

Unlike the JDOS folks, I had no intention of selling disk 
controllers; my market was people who had already bought a 
disk controller from Tandy and who had bought use of a 
Tandy ROM. Thus there was a strong argument that there was 
no copyright infringement involved in my selling such people 
a means of improving the ROM they had bought from Tandy. 
I realized that this argument was not entirely airtight, so I was 
always just a tiny bit worried that Tandy might some day 
come after me. But I gauged that (a) I was too small for them 
to bother with, and (b) if they did notice me they would 
probably just tell me to knock it off, rather than sue. Still, it 
was the copyright worries that caused me later to farm out the 
EPROM-buming to others, rather than handle that myself 

In addition to the compatibility advantage of being built 
around the Tandy ROM, there was also another important 
way in which I felt ADOS would be a significant advance over 
JDOS: configurability. I saw it as an enormous advantage that 
users of ADOS (yes, it stands for "Arts' DOS") would be able 
to configure the default printer baud rate, the drive step rates, 
and keysfroke macros prior to having an EPROM burned. 

Throughout the development of ADOS, software compat- 
ibility was always uppermost in my mind. I saw the biggest 
hazard to compatibility as arising from 64K software that 
used the area immediately above Disk BASIC where I in- 
tended to put my enhancements. The DISABLE command in 
ADOS was my attempt to solve this problem. In shutting off 
most of the ADOS enhanced features, DISABLE also freed 
up the memory above Disk BASIC for other uses, allowing 
"problem" programs to be made compatible. In the early days 
of ADOS, I made quite a few minor changes to achieve 
compatibility with one program or another, with the result 
that there soon remained practically nothing that wouldn't 
run under ADOS at all, and very few that required DISABLE. 

The compatibility issue also guided my choice of features to 
include in ADOS. Notably absent from ADOS are commands 
like DPOKE (double-byte poke). While such a command is 
convenient in some situations, the use of it within a program 
renders that program unusable by CoCo owners with stan- 
dard Disk BASIC. My aim was to create a more powerful but 
also compatible computing ENVIRONMENT. Hence, the 
extra commands of ADOS are those that would mainly be 
used from direct mode, rather than from within programs. 

Tandy's Little Wonder 

page 41 

As I began to develop ADOS, I was faced with the problem 
of what features to include. I knew I had a limit of 2K of 
space to work in. Two K does not sound like very much — a 
modest-sized BASIC program takes up more space than 
this — ^but I rapidly discovered that many BASIC enhance- 
ments could be accomplished using surprisingly few bytes. 
My addition of RUNM to the command set required only 1 8 
bytes; allowing COPY <filename> to <drive number> took 
37 bytes. This economy was made possible by the fact that 
many pre-existing ROM routines could be called to accom- 
plish parts of the task, and I made maximum use of such 
routines to squeeze as much as possible into my 2K. 

During the early phases of development, I did not feel 
squeezed for space at all; after putting in various enhance- 
ments to BASIC that had occurred to me early on, I still had 
quite a bit of space left, andbegan to wonder if I would be able 
to fill it. I began casting around for suggestions on Compu- 
Serve and in a Miami CoCo users' group I was then attending. 
Pretty soon, I had more than enough to fill 2K. I found myself 
poring over already-written routines, modifying the code to 
save a few bytes here and there in order to squeeze in this or 
that additional feature. The original Microsoft ROM code 
provided me with an excellent model to imitate; it is ex- 
tremely economically written with regard to accomplishing 
tasks using a minimal number of bytes. The code for the 
CoCo 3's Super Extended BASIC, written much later at 
Microware, is much less efficient. 

In April, 1984, when I had a preliminary version of ADOS 
ready, I sent a copy to Dennis Kitsz, hoping that the tie-in 
between his Lowerkit and ADOS' support of lowercase 
commands might lead to some sort of commercial collabo- 
ration. I heard nothing for months and then got a call from 
him. This was something of a thrill for me, since I had in my 
very early CoCo days been an eager reader of his CoCo 
articles in 80 Micro. We wound up sharing a booth at a 
number of RainbowFests, beginning with the September, 
1984 Princeton one at which ADOS officially debuted. 

When the CoCo 3 appeared, I wanted to have a version of 
ADOS that supported its features, and so began work on 
ADOS-3. There was very little room to add any features 
beyond those present in ADOS, since the ADOS enhance- 
ments entirely filled my available 2K. But I managed to make 
a little room by taking advantage of the fact that BASIC runs 
out of RAM on the CoCo 3, which allowed certain routines 
to be rewritten. Also, ADOS' ON ERROR GOTO and RAM 
commands were no longer needed, so that gave me some 
extra bytes to work with. I was particularly interested that 
BASIC should support the CoCo 3's double-speed mode, 
and modified disk and printer routines while adding FAST 
and SLOW commands. I also allowed ADOS-3 to be config- 
ured to boot up in 80-column mode. ADOS-3 was intro- 
duced in January, 1987 at the Color Expo in Anaheim, 

One thing that disappointed me about the CoCo 3 was that its 
internal ROM was soldered in. Had it been socketed, I would 
have strongly considered having ADOS-3 reside there, since 
the internal ROM contains plenty of free space (6K of which 
is taken up by the infamous "Three Stooges" graphic). To 
remove that ROM and install a socket would require some 
delicate soldering, which struck me as a highly undesirable 
requirement for a commercial product. Still, after releasing 
ADOS-3, I was itching to include quite a number of addi- 
tional enhancements — I had a backlog of ideas and sugges- 
tions by this time — and so began to consider a second 
possibility for where to place the required code. 

From the outset of ADOS, I had been aware that a disk 
controller could accommodate an EPROM with 16K of 
space rather than 8K. The problem was that this could only 
be done with controllers having a 28-pin ROM socket due to 
the fact that the only suitable EPROM was the 27128, which 
had 28 pins. All Tandy controllers had 24-pin sockets. A 
solution was to offer a 24-to-28-pin adapter for the Tandy 
controllers, and I had a source of these, a fellow by the name 
of Jim Smith that I had met at a meeting of the Miami CoCo 
users' group, who made them by hand. These were originally 
offered to ADOS users simply as a convenience, since 28- 
pin EPROMs were cheaper and easier to obtain than 24-pin 
ones, and since some CoCo EPROM burners were incapable 
of handling the 24-pin type. Since requiring an adapter made 
the product less attractive, I had decided to confine ADOS 
and ADOS-3 to an 8K EPROM, even though that limited me 
to 2K worth of enhancements. With the passage of time, 
though, two developments occurred that rendered an adapter 
unnecessary for many CoCo users to use a 28-pin EPROM. 
First, third-party controllers became considerably more 
popular, especially with the more experienceed CoCo users 
that ADOS primarily appeals to. These third-party control- 
lers all had 28-pin ROM sockets. Second, Tandy came out 
with the FD-502 controller, which contains a 28-pin ROM 
socket, although a minor modification is required to use a 
27128 EPROM. Therefore, I began to develop Extended 
ADOS-3 to fit together with ADOS-3 in a 16K EPROM. 

After having had to squeeze everything into 2K, watching 
every last byte, having another 8K to work in seemed like the 
lap of luxury, sort of like moving from a closet to a mansion. 
When I began, I never felt I would come anywhere near to 
using the whole extra 8K, even though I had quite a few things 
I wanted to add. These included a RAMdisk, which Marty 
Goodman had been begging me to put in for some time; a 
menu-driven utility for selecting files to execute, kill, load, 
copy, etc.; fast BACKUP and DSKINI; wild-card copy; file- 
dating that supported real-time clocks; block move and copy 
of BASIC program lines; and various other miscellaneous 
goodies. As things turned out, I came a lot closer than I 
expected; less than IK was left unused, and I had included 
pretty much everything on my "wish list". Extended ADOS- 
3 debuted at the Chicago RainbowFest in April, 1989. 

page 42 

Tandy's Little Wonder 


BASIC is normally an "interpreted" language. This means 
that the computer reads the BASIC code directly through a 
BASIC interpreter, as the CPU can't directly read the code. 
The interpreter converts the BASIC code into machine 
language- the native language of the CPU. The interpretation 
process is part of what makes BASIC slow compared to 
other languages. A good analogy is speaking to someone 
through an interpreter... how much longer does it take to get 
your message through, since you have to speak to the 
interpreter, then he/she to the other person? 

There are two BASIC compilers available for the CoCo now, 
WasatchWare's MLBASIC and Cer-Comp's CBASIC. It 

is important to note that compilers don't normally accept as- 
is BASIC code, they have certain formats the code must be 
written in before compiling. These differences are minor if 
one is already familiar with BASIC though. The Cer-Comp 
compiler requires much fewer changes (reportedly up to 
99% compatible with BASIC) than WasatchWare's, but is 
more expensive. 

A BASIC compiler takes the BASIC code, converts it to M/ 
L, then saves the M/L code in a form that the computer can 
run directly, bypassing the built in interpreter. This speeds 
the program up from 10-20 times over interpreted BASIC. 

Converting Between BASICs... 

not an easy task. 

One would think that converting a program between the 
CoCo 1/2 and the CoCo 3 would be quite simple. This is only 
true if the enhanced capabilities of the CoCo 3 are not to be 
used. The main problem is converting between PRINT@ and 
LOCATE statements. In cases where only the appearance of 
the screen needs changing, simple replotting of the text 
locations on screen is in order and relatively simple. If a 
program scans across the screen for input (such as a spread- 
sheet program), the programs just aren't easily converted. 
The PRINT@ function works very different from LOCATE 
(and vice-versa) when a formula is incorporated into a 
program to scan or plot locations on the screen. One can 
simply add and subtract from the PRINT@ value since all 
screen locations have their own, specific value. LOCATE 
must move up and down as well as back and forth, making the 
required fonnula more difficult to program- and entirely 
different from that required by PRINT@. 

The PRINT@ and LOCATE differences are just some of 
those encountered between CoCo 1/2 and CoCo 3 BASIC. 
The others can be easily documented by going through the 
manuals for both computers and comparing. Note that the 
CoCo 3 doesn't support the undocumented "semi graphics" 
modes of the CoCo 1/2. This is a function of the 6847 VDG 
that was not officially supported by Tandy. Only one com- 
mercial program is known to have used this mode, the Plug 
'N Power ROM Pak. 

"Converting" is probably NOT the correct term when IBM 
BASIC (B ASIC-A or G W-BASIC) is concerned. The author 
has done this before, and it isn't quite that easy. There are 
many differences between the two, to many to even begin to 
list here. Manuals for both BASICs can be gone through and 
the differences compared, possibly during a program "con- 
Tandy's Little Wonder 

version" exercise. One can also visit the local library and see 
if BASIC Program Conversions (HP Books, 1984, ISBN 
0-89586-297-2) is available. This book hsts all the com- 
mands and equivalents of IBM/compatibles, Commodore 
64, Apple IIe/II+, TRS-80 Model III/IV, and CoCo 1/2 
BASICs. There is room for notes to be made on the CoCo 3 
commands, but they aren't included in the book. These other 
computers could theoretically be converted to/from, but 
only the TRS-80 models would be practical, as the Commo- 
dore and Apple BASICs have many unique commands. 

PEEK, POKE, and EXEC locations are different for all the 
previously listed computers! One must find out exactly what 
the original program expected to find at the specified memory 
location and write a routine (or find a similar operation on 
the target machine) to emulate the PEEK, POKE or EXEC 
operation. It can be extremely difficult, sometimes virtually 
impossible, to rewrite a program that contains a lot of these 

When converting from the IBM to CoCo, it is much easier 
to convert to the CoCo 3 because the LOCATE commands 
are similar. The format for the CoCo 3 is "LOCATE x,y" 
(column, row) while the IBM is the opposite ("LOCATE y,x" ; 
row, column). The CoCo 3 numbers rows and columns 
beginning with (0-79, 0-24) and the IBM numbers begin- 
ning with 1 (1-80, 1-25). If going from the IBM to CoCo, 
many routines will have to be totally rewritten. Going from 
the CoCo to IBM is easier, as CoCo BASIC is simpler than 
the IBM version. Converting to/from the CoCo 1/2 has the 
same major problem as converting to the CoCo 3- the 
PRINT@ and LOCATE command disparities. 

page 43 

Other DECB Programming Languages... 

Other programming languages were written to operate in 
conjunction with DECB over the years. These include "C", 
FORTH, PASCAL, and LOGO. Only the first two are 
currently available. 

A new company (Infinitum Technologies) recently re- 
leased a new "C" compiler for the CoCo, called simply 
"CoCo-C", which is very similar to the OS-9 "C" compiler- 
the same reference material is usable with minor differ- 
ences. The best book to get for reference is "The C Program- 
ming Language" by Kemighan and Ritchie. The current 
edition is based on ANSI "C", but the differences between 
the original "C" language and ANSI are minimal. The main 
advantage of the "C" language is that it can be transported 
between different computers and operating systems (usu- 
ally) with minimal changes. 

The basic "C" commands are the same for all compilers. The 
compiler is different for each computer/operating system. 
"Source code" (the actual list of commands, similar to a 
BASIC program listing) is written with an editor or word 
processor then saved in ASCII format and compiled on the 
desired computer. The differences come in because some 
computers have added commands that take advantage of 
differences in the hardware and operating systems. One 
example is the graphics resolution on a CoCo and on an IBM 
compatible with VGA monitor. Any high resolution graphics 
on the IBM would have to be changed to the lower resolution 
of the CoCo before the program could be compiled with a 
CoCo "C" compiler. Some operation systems have more 
math capabilities than the CoCo also. These differences can 
be overcome, but only with more programming. Text based 
programs usually compile with a minimum of changes. 
Many OS-9 commands have been ported over from UNIX 
computers through "C". "C" wasn't as popular with CoCo 
BASIC (it was available for the CoCo early on, but only as a 
subset of the full "C" language) as it has been for the OS-9 
crowd, but renewed popularity of "C" across all computers 
should change that. It will also mean converting a program 
from one computer to another won't require as much work 
as it has in the past, as a program written on a CoCo in "C" 
should easily transport to a more powerful machine. 

The package from Infinitum is more than just a compiler, it 
contains all one needs to start programming in "C" except a 
text book! Included in the software package is a text editor 
for creating/editing source code (any word processor may 
also be used), the compiler, an assembler for creating 
assembly language files, library/linker to create stand- 
alone binary files, and a command coordinator to integrate 
the above into a user fi-iendly enviroment. 

CF83 FORTH is available from BDS Software. The fol- 
lowing description was written by M. David Johnson. 

BASIC has 157 commands in a CoCo 2 and 185 commands 
in a CoCo 3 This is quite a lot and when you combine 
commands to make a program, the number of things you can 
accomplish with your CoCo becomes very large indeed. But 
there ARE limits. Because there are only so many com- 
mands, there are some things that youjust can't do in BASIC. 
And because BASIC has to interpret every command as it is 
encountered, BASIC tends to be rather slow. Commands 
can't be easily changed or new commands easily added, 
unless you are intimately knowledgeable concerning every 
internal idiosyncrasy of the CoCo, and an adept assembly 
language and machine language programmer to boot. It takes 
hours of development and debugging time also. 

So, you can choose slow, easy BASIC, or fast, difficult 
Assembly Language. But, what if you want fast and easy 
both? CF83 FORTH is not a perfect solution, but it comes 
close. CF83 FORTH is almost as fast as Assembly Language 
and almost as easy to use as BASIC (once you get past the 
initial learning phase which is admittedly not trivial). 

The first FORTH was written by Charles Moore in 1971 to 
be a data acquisition system for the National Radio As- 
tronomy Observatory at Kitt Peak in Arizona. FORTH has 
since grown into a major control language for the entire 
astronomical community. 

But FORTH is no longer limited to astronomy. FORTH is 
also currently used in image processing, robotics, 
servomotion controls, electrophoretic separation of bio- 
logical materials on the space shuttle, and many small-scale 
imbedded systems. These systems all require very compact 
code in small packages, and that is just what FORTH was 
designed for. But FORTH also does well in truly huge 
systems. A FORTH system currently controls almost all the 
operations of the main airport in Saudi Arabia. The game, 
"STARFLIGHT", for the PC is written entirely in FORTH. 

Another FORTH system is Amtelco's massive EVE (Elec- 
tronic Video Exchange) which has become the predominant, 
largest, and most sophisticated messaging system for the 
telephone answering service (TAS) industry. EVE has cap- 
tured 70 percent of the TAS market and consists of about 
100,000 lines of source code. Despite its "large" size, EVE 
comfortably runs on a single 10 MHz 68000 Motorola 
microprocessor. Olaf Meding of Amtelco says, "FORTH is 
much more than a computer language. FORTH is a complete 
programming environment, and even more it is a philosophy. 
The concept of simplicity is what makes FORTH so effec- 
tive and powerful." 

page 44 

Tandy's Little Wonder 

When you LOAD and RUN a BASIC program, the BASIC 
interpreter analyzes each program line, translates it into 
machine code, and then executes that code. BASIC program- 
ming is interactive: you can make changes in your program 
and test those changes immediately. This makes program 
development and debugging comparatively easy. But, be- 
cause BASIC must analyze and translate each program line 
every time the program is run, BASIC programs are also 
comparatively slow. 

If you use an assembler (such as EDTASM) or a compiled 
language (such as C, PASCAL, or a BASIC compiler), you 
write your program in an ASCII source code file and then 
assemble or compile and hnk it to a machine language object 
code file. When you want to run the program, you simply 
LOADM and EXEC the machine language object code file. 
The machine language executes directly: it doesn't have to 
be analyzed and translated each time the program is run. 
Therefore, machine language is comparatively fast. But 
assemblers and compilers are not interactive: if you make 
any changes in the program, you have to re-assemble or re- 
compile and re-link it before you can test the changes. This 
makes program development and debugging difficult. 

A threaded interpreter builds fully analyzed and translated 
machine language code by compiling new words as you write 
them into the program. A FORTH program consists of a list 
of word definitions, where each word definition is simply a 
list of previously defined words. Once it has been defined, a 
FORTH word is like a BASIC subroutine - it can be called 
over and over, and it can be called from other subroutines 
which themselves can be called over and over, etc., etc.! ! 

Aha! The best of both worlds! So... Where's the catch? First 
of all, you have to learn a whole new way of thinking. Forget 
everything you've ever learned about computer program- 
ming! Start from scratch... 

CF83 FORTH does not use floating point numbers; it only 
uses integers. 5 is a legal number in CF83 FORTH, but 5.0 
is not. This is both an advantage and a disadvantage. Integer 
arithmetic is MUCH faster than floating point arithmetic, so 
anything that can use integer arithmetic (e.g. screen graph- 
ics) will make BASIC really look like a turtle. And if your 
application really needs floating point results, you can write 
new floating point routines to provide them. 

CF83 FORTH is an Extensible, Stack Oriented, Reverse 
Polish, Threaded Interpreter. FORTH is Stack Oriented. 
BASIC and other languages are Variable Oriented. In BASIC, 
you store numbers in variables and then use the variable 
name whenever you want to access the number or pass it to 
a subroutine. FORTH also uses variables when it has to, but 
most of the time it stores numbers on a stack and passes 
numbers to other words via the stack. 

A stack is a simple Last-In, First-Out (LIFO) storage device. 
Suppose you have a handful of pennies and you stack them 
one on top of the other on your desk. Now, if you want a 
penny, you take it off the top of the stack. You don't try to 
take it from the bottom or the middle of the stack because the 
entire stack would fall down. So, the last penny you put on the 
stack is the first penny you take off the stack, i.e. LIFO. The 
stack orientation saves memory - less memory is devoted to 
variable storage. You might think that the variable memory 
you save would be offset by the memory needed for the 
stack. But BASIC and other languages also use stacks. 
Programmers just aren't aware of those stacks because 
programmers aren't allowed to use them directly - the stacks 
are reserved for internal use by the language itself 

Stack operations are more efficient if you use Reverse 
Polish Notation (RPN). RPN should be familiar if you own 
one of the more expensive Hewlett-Packard Scientific Cal- 
culators. Some less expensive HP calculators and most 
others use Algebraic Notation (AN). AN is familiar and easy 
to understand. If we want to add 3 and 5 with an AN calculator, 
we simply press: 3 + 5 = and the answer 8 appears in the 
display. With an RPN calculator, we press: 3 ENTER 5 + and 
the answer 8 appears in the display. The answer is the same, 
but the procedure isn't as clear or natural. Similarly, under 
BASIC, we would enter: PRINT 3 + 5, but in CF83 FORTH 
we would enter: 3 5 + . Algebraic Notation makes things 
easier for us. But RPN makes things easier (spell that FAS 
T E R ) for the computer. FORTH programmers will readily 
testify that the additional speed is well worth the added 

FORTH is Extensible. In BASIC and other languages you 
have a set of reserved operators and keywords like +, -, *, / 
, PRINT, INPUT, RETURN, STRINGS, etc. These are the 
only words you can use in writing programs. If you want to 
PRINT "This Phrase" at three different points in the program, 
you either have to repeat the program line three times: 

110 PRINT "This Phrase" 
260 PRINT "This Phrase" 
430 PRINT "This Phrase" 
or set up a subroutine and call it three times: 

llOGOSUB 1000 

260 GOSUB 1000 

430 GOSUB 1000 

1000 PRINT "This Phrase" 

1010 RETURN 

But in CF83 FORTH, when you define a new word, you can 
use it just like any other word. If you define the word ptf: 

: ptf ." This Phrase " cr ; 
which does the same thing as the BASIC program line PRINT 
"This Phrase", then you can use ptf anywhere and it will print 
the phrase at that point, i.e.: 

ptf... ptf... ptf 
You have just added a completely new keyword - you have 

Tandy's Little Wonder 

page 45 

EXTENDED the CF83 FORTH language. This is one of the 
most important features of FORTH: you can extend and 
customize it to meet your own particular needs. And, you can 
do so almost without limit! (Except, of course, that you can't 
use the word until after you have defined it). 

CF83 FORTH is modular. Unlike other languages where you 
have to buy the entire package whether you need it or not, 
CF83 FORTH is organized onto individual disks that you can 
buy one or more at a time. You only buy what you need, and 
only when you need it. As an additional savings, each module ' s 
instruction manual is stored on the module's disk (printed 
manuals are available though). Prices are significantly lower 
without the printed manuals. You can view the stored manual 
on the screen and, if you need one, you can print a hardcopy 
on your own printer. 

CF83 FORTH is a 1983 Standard FORTH for the 64K CoCo 
2, 128K CoCo 3, and 512K CoCo 3, with at least one 
standard single sided 35 track floppy disk drive. As of 
January 1993, the CF83 FORTH system included the fol- 
lowing modules: 

CF83: FORTH-83 Standard Required Words. This module 
is the foundation - you must have this one for any of the 
others to work). 

CF83-1: Technical Reference Manual 
CF83-2: FORTH Tutorial 

CF83-3: Block Editor. You need a FORTH editor to write 
your programs in CF83 FORTH. Unless you can write your 
own editor, you'd better get this one! 
CF83-4: Double Number Set. CF83 only handles 16-bit 
integers by itself This set lets you handle 32-bit integers. 
CF83-5: Assembler Set. Integrate machine code routines 
that have to be real fast with this full-featured assembler. 
CF83-6: System Extension Set. Helps you define new 
control words more effectively. 

CF83-7: Controlled Reference Set. Words that perform 
many different functions. Includes recursion, block control, 
and system maintenance routines. 

CF83-8: Uncontrolled Reference Set. Includes case struc- 
ture, string operations, printer control, and more. 
CF83-9: PMODE Graphics Set. Use PMODE graphics in 

CF83-12: Turns your CF83 FORTH programs into binary 
files that will EXEC directly from BASIC. Includes system 
saving and general disk file handling & creation. 

The entire set could be purchased for as little as $120, not 
bad for such a high-level language. Most general users would 
only need three or four modules though, bringing the cost 
down to under $50. Just recently, however, the main FORTH 
module (CF83) was placed into the Public Domain, making 
this language even more attractive! Contact BDS Software 
for more info on PD modules. 

Modules that were under development at the time this was 
written include: 

CF83-10 : HMODE Graphics Set. Use high-resolution CoCo 

3 graphics. 

CF83-11: Sound, Joysticks, Timer, & Random Numbers 

CF83-13: Floating Point Numbers Set 

CF83-14: Trigonometry Set 

CF83-15: Complex Numbers Set 


(1) Medding, Olaf; "FORTH-Based Message Service"; 
FORTH DIMENSIONS, Volume XIV, Number 5, January- 
February 1993; FORTH Interest Group, P.O. Box 2154, 
Oakland, CA. 94621 

FORTH09 is a CF83 FORTH implementaion for the OS-9 
operating system. It is also available from BDS Software. 

Actual machine language (M/L) and assembly lan- 
guage (A/L) programming is beyond the scope of this 
book. Machine Language refers to the actual code that the 
MPU reads directly. One CAN write directly in this code, 
but most programmers use an Assembler to put the code 
together, thus the term Assembly Language (M/L and A/L 
are usually used interchangeably). 

Writing directly in M/L requires poking the certain values in 
the correct memory locations. This is exactly what is being 
done when a BASIC program has a routine like the one shown 
in the double speed program (PEEK, POKE, EXEC En- 
hancements, lines 440-480). A data set (in this case A$) 
contains a list of values that is then poked into memory by a 
short BASIC program. 

An assembler makes life easier for the programmer. The 
program is written in mnemonic instruction code with an 
editor (usually bundled with the assembler... Tandy's 
EDTASM+ name comes from EDiTor/ASseMbler). The 
instruction code is a set of instructions that are programed 
into the CPU itself These instructions operate on and 
access data in different ways through addressing modes. The 
6809 has 59 instructions and ten addressing modes for a 
total of 1464 different operations. Variations of these 
modes bring the total number of modes up to 19. This code 
must then be assembled into a list of binary data (m/1 code) 
that the CPU can use directly. 

Mnemonic instructions are abbreviations of what the com- 
mand actually does. The instruction itself (ADDB, for 
example) is called the "opcode" (operation code). This is 
followed by a value for the instruction to act on or with, 
called the "operand" or argument. Together, the opcode and 
operand define exactly what the instruction does. The mne- 
monic "ADDB #1" means "add the contents of register B in 

page 46 

Tandy's Little Wonder 

the CPU to the number 1 and put the result back in the B 
register" . The "#" sign defines a decimal value in EDTASM+. 
Other assemblers may use a different designation. 

The above description is a bit simplistic, as any A/L pro- 
grammer will readily testify. A full discussion on M/L and A/ 
L programming is beyond the scope of this book. Check the 
"Library" section for recommended texts. 

As for assemblers, several were available for Color BASIC. 
Tandy's own EDTASM, EDTASM+, and Disk EDTASM 
were naturally popular. So was Micro Ware's MACRO80C, 
which for a time was even more popular than the Tandy 
product! Used copies of these are likely to show up with used 
CoCo systems. If the manuals are intact, they are still good 
products to have. There are many enhancements available for 
the Tandy product available from Delphi or FARNA Sys- 
tems. FARNA also sells an enhancement that adds support 
for the Hitachi 6309 CPU. Versions for all CoCo models 
are shipped on the same patch disk. 

The only currently supported Color BASIC editor/assem- 
bler is Cer-Comp's EDT/ASM III. It is designed to take 
advantage of the added features of the CoCo 3, but versions 
are available for the CoCo 1/2 as well. Cer-Comp also sells 
a "disassembler", which breaks machine language programs 
down into opcode and operands. A skilled A/L programmer 
could use a disassembler to break down an existing program, 
make modifications to the code, and then reassemble a 
modified version. This takes quite a bit of practice and 
patience! Although A/L programs are much faster than 
BASIC, debugging is harder and more time consuming. 

The only OS-9 assembler came with OS-9 Level I and the 
OS-9 Level II Developers Pack. The assembler was shipped 
with Level I instead of Basic09, which was sold separately. 
Tandy wised up when Level II came out and included Basic09 
instead of the assembler, which was relegated to the 
Developement Pack. The Level I assembler works fine with 
Level II- in fact, the Level I and Level II assemblers are 
virtually the same. 

Binary and Hexadecimal Conversions - WesRatdiff 

Regardless of programming language used, there will come 
times when hexadecimal and binary numbers will be 
needed. The following method works well and is rather 
simple. Most other methods require tables of numbers. 
These work, but require looking up each "nibble" (4-bit half 
of an 8- bit byte) separately. Wes' method is a bit easier, 
especially if one needs to do conversions without tables. 

As an old assembly language programmer, hexadecimal 
(hex) is second nature. But anyone can calculate hex in their 
head without resorting to tables. Just break a number into 
nibbles. That is, each hex character represents a value from 

to 16. If you have the number &HF2, for instance, think of 
it as "F" and "2". Each character in hex is represented by 4 
digits in binary. "F" in binary is 1 1 1 1, and "2" represented in 
binary is 0010. So that &HF2 (hex) is the same as 111 10010 
binary. A little practice and it will come naturally. All you 
have to remember is the values from to 1 5. 1 6 bit values are 
interpreted the same way, as four nibbles. 


















































If you want to convert a decimal number, you can start at the 
left. If you're working with an 8-bit number, bit 7 represents 
128 decimal (bits numbered 0-7, right to left). So if your 
number is greater than 128, write a 1 . If not, write a 0. If you 
wrote a 1, subtract 128 from your decimal number. Move to 
bit 6. Here a bit represents 64. Repeat the above exercise, 
writing a 1 if the number is greater than 64, then subtract 64 
from the number and go on to the next bit, which represents 
32. Each lesser bit represents half the bit before it. Continue 
until you're at bit 0. The opposite is also true. In the binary 
representation above, we have a 128,64,32,16, no 8, no 4, a 
2, and no 1 . Add 'em up and you've got your decimal number. 

To convert a decimal number to hexadecimal, convert it to 
binary first then break it down into nibbles. Write the values 
of the nibbles down in binary from the sixteen values above. 
For an eight bit number add the values together. For a 16 bit 
number, add the first two and the last two nibbles (two eight 
bit bytes) and write those values down. Multiply the first byte 
(on the left) by 256, then add to the value of the second. 

Tandy's Little Wonder 

page 47 

Micro W8.rC S OS -9... aheavy-dutynOSforCoCo. 

An Introduction to OS-9 Rick Ulland 

Do you need OS-9? Maybe not! Many users view their 
computer as an appliance. Any good appliance should per- 
form it's job as easily as possible, without much muss or 
fuss. For this type of use, DECB cannot be equalled. You 
cram is a disk, type run, and away it goes. The only problem 
with 'computer as appliance' is, they just aren't that good yet! 

Making it simple usually means leaving things out. hidividual 
programmers can write any capability into any program, and 
sometimes do, but this approach to upgrading has proven 
less than impressive, resulting in giant, expensive programs 
that each do things their own way. OS-9 attempts to put many 
of the most wanted features of modem computers where 
they belong- in the operating system. Of course you only 
have to learn everything once, but sometimes it seems you 
have to learn everything first! The natural tendency is to ask 
somebody what the heck is going on. Those fortunate few 
who know a fellow OS-9 user who lives nearby enjoy a pretty 
painless introduction. The rest of the world has to settle for 
hurried conversations carried out over telephone or modem, 
and even though the other person is really trying to help, 
there is just too much information to pass on in a few 
minutes. In an attempt to cover as much ground as possible, 
the helper may lapse into that dreaded variant of technobabble 
know as the buzz-word. 

A Very Buzzy Bee 

OS-9 promises (and delivers) quite a lot of capability in a 
very small package- watching Level II run on a 6809 is an 
awesome sight to folks familiar with the chips' limitations in 
memory space and speed. You may well ask, why worry 
about memory? After all, there are 2 megabyte RAM up- 
grades available. Well, the rub is the 6809 can only address 
64K at a time. DECB users are quite familiar with this 
limitation. Even a 512KCoCo only shows 24K free (the rest 
of it's 64K ate up by the basic ROMs and some data space). 
BASIC does gain some use of the extra ram by moving the 
graphics screens out of the base 64K area, but all of the 
program code still has to fit there. OS-9 Level II doesn't 
remove this barrier, but does work around it nicely, by 
splitting the whole into separate groups. 

A process is up to 64K of code and data. The difference is 
under OS-9 you can have as many processes as you have 
memory for, while under DECB you have one. This is the 
reason some OS-9 programs are split into two parts, for 
example word processors will be divided into a separate 
editor and print formatter. This way the whole package can 
use 128K (2 processes) instead of 64K (one process). 
Processes can be connected together from the command 
line as well. 

When someone speaks of pipes, they are talking about 
connecting one process' output directly to another ones' 
input. On the command line, a pipe looks like an exclamation 
point- procl ! proc2. There are two reasons to do this- 
either to get around the memory problem, or to make a single 
utility more useful. We'll get into this more later. 

There is still a problem with the total RAM available. The 
practical problem is fitting the operating system into the 
machine. There are 3 ways to do this. The DOS can be kept 
small and simple, or simply demand the machine grow larger 
and larger, so the whole thing will fit. (the disk drives also 
have to get faster and faster, so the thing can be loaded the 
same day, and larger so the thing will fit on a decent number 
of disks... in other words, it can be like MS-DOS). Micro- 
ware took the third tack. OS-9 (and OS-9 programs) are split 
into modules, which can be loaded as needed, or unlinked to 
free up memory. You'll see this in action when running 
config or os9geii- out of all the things that could go into OS- 
9, the user picks the ones he needs. 0S9gen packs them into 
a small, quickly loaded boot file. 

There are a few additional space saving tricks. First all of 
these modules are reentrant. One copy in memory can be ran 
many times simultaneously. Each separate iteration gets it's 
own block of data space, but uses the same copy of the code. 
The other trick involves how a module is run. For example, 
the OS-9 prompt you see on screen doesn't come from OS- 
9 itself, but a special program called shell. When you type 
a command, shell reads it, then runs that module. It doesn't 
go away, but waits in the background for the new process to 
finish. This is called forking a process. The old process 
(known as the parent) is still around, just hidden in the other 
fork of the road waiting for the new process (the child) to 
finish. Now, if you really need every byte of RAM, you can 
chain the new process, using the ex command. The parent 
shell is killed, freeing up the memory it used, but if the child 
process ends, the window seems to lock up! It hasn't really 
crashed, but there is nothing for it to run. 

To keep track of all these modules, OS-9 has a special 
directory. Mdir (module directory) lists all the modules is 
memory, and keeps track how many times each one is being 
used. The Unk count starts at one if a module is loaded, or 
if it's just called, and goes up one each time it is executed, 
then down by one when it's finished. If it hits 0, that module 
is dropped and you get the RAM back. So a module that was 
run from the command line, and not loaded first, disappears 
when it's finished. There are two special commands to deal 
with this- link bumps the number up one so a module will 
never be dropped, while unlink reduces it one. Enough 
unlinks and it disappears! 

page 48 

Tandy's Little Wonder 

With all these modules and processes lurking around, things 
could get a little skitzoid! The input and output can't be left 
to each process, else running your OS-9 system would 
resemble a bad adventure game. The unified I/O system 
helps keep the data organized. There is a path leading to and 
from each process, the standard path being keyboard to 
process to screen. But it's negotiable. Redirection can be 
used to connect a process to any hardware device, using the 
greater/less than arrows. So 'list file' goes to the screen, but 
'list file >/p' goes to the printer, and 'list file >/t2' sends 
it out the RS-232 port. The slash letter part of these 
commands is called a pathlist, and can get quite long 
sometimes- /dO/cmds/icons/myicon is a pathlist meaning 
'look in drive 0, find the cmds directory, look in cmds, 
find the icons directory, look in icons, find the file 

Lets take an example that uses both redirection and pipes. 
DSave looks at a disk, and outputs all the copy commands it 
would take to copy the disk one file at a time. 'Dsave /dO / 
dl' would just print this list of copy commands to the screen 
(standard path). Not terribly useful. 'Dsave /dO /dl >/dO/ 
file' would send these to a disk file on drive 0, which you 

could run later. A little better 'Dsave /dO /dl ! shell' 

pipes this list of commands directly to a shell. Since shell's 
job is to run commands, and dsave outputs commands, the 
disk gets copied immediately. So far, we have been talking 
about space- the pile of actual things (modules) that make up 
an OS-9 system. Now we have to address time. 

The primary design goal of OS-9 is that is be a real time, 
multi-tasking operating system. This causes some unique 
problems. Since computers can only do one thing at a time, 
all multi-tasking systems have to switch the CPU between 
each process that's waiting in line for CPU time, a system 
known as time-slicing. There are two options. The first is 
cooperative multi-tasking, where the individual programs 
decide when, or if, they are going to give up the CPU. This 
idea has some problems- you have to buy special programs 
written to cooperate, and any program can hog the machine. 
Definitely not real time. OS-9 uses pre-emptive multi- 
tasking. The individual programs all think they own the 
machine, only the operating system knows for sure. Every 
process has a priority, which tells OS-9 how much time to 
give it. This priority is up to you, and it's a handy power to 
have. Bumping a process priority way down reduces the load 
on the machine to the point where the user can't tell it's 
running. It will get done eventually, and in the meantime you 
can do other things. This helps, but there is still a problem.... 

Unlike with DECB, a program can't just sit on the hardware. 
For instance, a terminal program might be switched out when 
a new character comes in. Since the terminal program 
doesn't know it's being switched in and out, it would miss that 
character. This is where interrupts come in. Hardware 
interrupts inform OS-9 it's time to go take care of the 
hardware, regardless of what else is going on. Another 

concern is wasting time. If a process is waiting on keyboard 
input, for instance, there is no need to give it CPU time until 
something is typed. So, a process can sleep, giving up it's 
CPU time, until a signal (the software version of an inter- 
rupt) comes along. 

With all this multi-tasking ability laying about, there has to 
be some way to use it. The first way is by using the CoCo 
Windowing system. This system establishes virtual con- 
soles, switching the screen and keyboard between separate 
processes. It doesn't matter which window is visible on the 
screen, they all run full speed (depending on priority). OS- 
9 considers each window to be a separate hardware device, 
with it's own keyboard and screen. 

The second possibility is using background tasks. DECB 
users are no doubt familiar with using colons to put more 
than one command on a line. The same thing can be done in 
OS-9 using semicolons- 'list file>/p; dir /dO' first lists 
'file' to the printer, then does a directory of drive 0. But there 
is another command line separator- the ampersand, 'list 
file>/p& dir /dO' lists the file to the printer, and at the same 
time puts the directory on screen. Just want your prompt 
back? 'List file>/p&' immediately returns an OS-9 prompt. 
Free printer buffer! 

There is a third way .Although Tandy didn ' t include them with 
Level II, owners of the Level II Development System will 
find the utilities tsmon and login included. These allow 
other people to log in to your CoCo. This can be another 
computer on the same desk or somebody halfway 'round the 
world using a modem. The remote user gets his own shell, 
and can run any programs you let him (this is why OS-9 files 
have both 'public' and 'owner' attributes). So not only is 
your CoCo a multi-tasking computer, it is multi-user ca- 
pable as well! All you need is the above commands and a 
couple serial ports, cables, and terminals (or other comput- 
ers... a good use for an MS-DOS machine!) 

What OS-9 Does for You 

The preceding discussion has delved pretty deeply into what 
OS-9 is, but hasn't really said anything about what you, the 
user, gains. Here are a few of my favorite things; 

One thing that can't be emphasized enough... any capability 
of the operating system is usable by any program. Some 
DECB programs support multiple windows or 80 track disk 
drives, but under OS-9 all programs do. 

The big feature is windows. I often find myself doing more 
than one thing at a time- perhaps I'm writing a letter and need 
some information from a disk file, or from a spreadsheet. 
Just a clear key away, there is a separate screen waiting ! I also 
use windows to answer my on-line E-mail. One window 
displays the mail captured, while the other has a text editor 
running in it for the replies. Even simple things, like not 
having a formatted disk ready, are easy to fix with that 

Tandy's Little Wonder 

page 49 

separate window (or two or three... as many as needed 
provided there is memory for them!) always ready and 


Since all of OS-9's commands and utilities are really sepa- 
rate modules, the user isn't stuck with any of them. In fact, 
new utilities and system patches probably represent half of 
the software written for OS-9. Dot'i like the way the copy 
command works? Use a different one! Need to read and write 
MS-DOS disks? There is a patch to fix the disk driver so it 
can do that. Most of these patches are available free from 
BBS services, or on disk form from several sources. 

If you enjoy programming, OS-9 is the key to a whole new 
world. Microware BASIC (aka Basic09) can be used to write 
everything from old fashioned line number oriented pro- 
grams to structured, modular code your computer science 
professor would be proud of (try to get a copy of "The 
Official Basic09 Tour Guide" from Microware... it even has 
some general OS-9 hints)! There are plenty of languages to 
work with- besides Basic09, there are C and Pascal compil- 
ers, FORTH09, and two assemblers were produced. And, 
you don't just have two or three 'documented ROM calls', 
but literally hundreds of system calls to make things easy. 
The unfortunate thing is that unless a new ot used copy of the 
Tandy version of these languages is found, they are pretty 
much unavailable. The exception is FORTH09 firom BDS 
Software (see the article on FORTH under "Other DECB 
Programming Languages") 

Shell scripts can automate a complex set up process. Lets 
assume a program runs best with a RAMdisk, but you don't 
usually have one nmning. Make a text file containing the 
commands to start and format a RAMdisk, and run the 
program. Typing the name of the text file as a command will 
run each line just as if it had been typed at the OS-9 prompt 

Then there is Multi-Vue... Guru types don't like to use 
Muiti-Vue, since it's a little slow. Not many commercial 
programs come with the icon and aif file included, either. 
B ut if you have the patience to set it up and get the icons and 
aifs from an on-line service, (or make your own) it does 
make a pretty neat GUI. And you don't have to worry about 
turning your kids loose on the CoCo! 

And last, a powerful operating system greatly reduces the 
number of programs the user has to own. For example, OS- 
9 comes with an editor. It's not a great text editw, but it can 
do the job (of course, there are better ones available free 
from on-line services). It also has a list command, which can 
list any file to any hardware device. So, it's possible to write 
a short letter and print it without using a 'program ' at all, just 
the operating system! 

OS-9 isn't without it's share of problems though. Anything 
with the power and versatility of OS-9 is usually more 
complicated also, so there is more to learn. The syntax for 
the commands is entirely different from DECB, so that has 
to be learned also (one reason many DECB users find it 
easier to cross over to MS-DOS machines is that the com- 
mand syntax is so familiar). Last but not least, the system is 
just adequate as shipped by Tandy. There are lots of addi- 
tional commands that can be added and patches to improve 
the raiginal commands. Seating through those can be diffi- 
cult at best, which is why I made a disk of extra commands 
and patches with an automatic patching program (available 
from CoNect or FARNA Systems). The OS-9 manuals 
from Tandy arc not the best, to put it mildly. "The Complete 
Rainbow Guide to OS-9" (still available from Falsoft) will be 
very helpful, as well as a copy of "Start OS-9"... if it can be 
found or borrowed. "The Complete Rainbow Guide to OS-9 
Level n Vol. I: A Beginners Guide to Windows" (Falsoft) 
wiU help Level n users with windows, but assumes a basic 
understanding of OS-9. 

All this makes it hard for the long time DECB user to make 
the jump to OS-9. Be patient and get help from an on-line 
service, local BBS, user group, ot local OS-9 user. OS-9 will 
seem difficult at first, but like anything else, you will gain 
ccHifidence and skill with practice. You may even fmd, in 
time, that you actually like OS-9! 

OS-9 Unleashes the 

Full Potential of 
Your Color Computer 

Get More Power With OS-S"* 

OS-9 OI«tc Operating System. A reaMtme operating system 
that accesses the entire memory of the 64K Extended BASIC 
Color Computer. OS-9 includes a powerlul edrtor/assembler. 
plus functions for disk and terminal input/output, software 
memory management and multitaskrng. 26-3030 . . . 69.95 
OS-9 Level Two Disk Operating System. A multitasking 
reaMime operating system similar to OS-9. Put with enhance- 
ments to support 512K RAM and dual speed on the Color 
Computer 3. Includes standard input/outpui drivers and 

BASIC-09 2&-3031 79.95 

New! OS-9 Level Two Development System. Complete 
editor/assembler with fullscreen editing and specialty input/ 
output drivers lor the Color Computer 3. Requires OS-9 Level 

Two 26-3032 99.95 

New! Mulli-Vue. A user-fhendly graphics interlace for OS-9 
Level Two programs. "Window" and access multiple applica- 
tions on your Color Computer 3 in a manner similar to the 
operations ol our popular DeskMate' software. You'll be able 
to run and use separate programs simultaneously, saving txiih 
lirrie and trouble. Insert programs like Dynacalc. TSWORD. 
TSEDIT. TSSPELL. OS-9 Screen Print and OS-9 Profile (be- 
low) to create your own integrated applications package. 
Multi-Vue even includes two handy built-in applications of its 

own: calculator and scratchpad. 26-3035 49.95 

OS-9 Screen Print. Pnnt high-res Color Computer graphics. 
Reauires dol-matnx pnnter with bit-image mode tor B&W. 
Requires OS-9 DOS. 26-3221 14.95 

Sptcinlisis in sysltm softwart for 6 8- family microprocesson sitici 1977. 

CS-S and BASIC09 are Irademarks of Microware and Motorola 

Miawfan Sysemi Corporation 
I86^> N.w. ri4cri street 
Dfs Moinei, kwa 50322 
TrWpTKXK 515(224-1929 
, Ttlex 9tO-520'2S35 

page 50 

Tandy's Little Wonder 

ISUppOrt... where to go from here... 

Where does one go for support? The local Radio Shackprobably won'tbe much immediate help (see Tandy 
below). Writing to a magazine takes to long. You know of no one in your area with a CoCo or any more 
knowledge of thebeastthanyou. Whatnext? There are five options listed below. They are: 1 . Tandy (Radio 
Shack) . . . what little support they DO offer. 2 . User Groups and Clubs 3 . Current Vendors 4 . Annual Shows 
5. Telecommunications (requires a modem... GET ONE! ! !) 

Local vendors usually know most of the CoCo people in an area. Contact them for assistance. They may 
be willing to supply a short mailing list of people nearest you. Don't be disappointed if a vendor IS NOT 
wiUing to do this, however, as customers expect a degree of confidentiality. Most users are not opposed 
to other CoCoist having their address, but some may be. Vendors may not want to risk losing customers! 

1. Tandy Support? 

Yes, there is still a small amount of support from Tandy/ 
Radio Shack. And I do mean small. It is extremely RARE to 
find someone in a Radio Shack who even knows what a CoCo 
is any more (it was usually difficult to find someone who 
knew much about the CoCo even in its prime years!). Yet 
Tandy didn't give up on us completely. As a matter of 
company policy, repair components are kept available for 
ten years. This doesn't mean that a populated motherboard 
may still be available- it means that the special chips should 
be available for repair purposes. If a catalog number is 
known, chances are the local Radio Shack can still order 
most cables and printer ribbons. 

To find out just what is available it is best to call Tandy 
National Parts directly, though a helpful local dealer may 
do it for you. You will need the catalog number of your CoCo 
or peripheral. Find this BEFORE calling. If the particular 
part number is known, have that ready also. Then call Tandy 
National Parts at 817-870-5600. 

Radio Shack stores can still get some software. Ask the local 
store for an Express Order software catalog. There will 
be a phone number to call in the catalog as well as a listing 
of available programs. The local store may assist in placing 
an order or place the order for you. Manuals for Express 
Order software may be photo copied, not printed. 

Two other Tandy services may be of limited assistance. 
Hardware Support (817-878-6875) maybe able to answer 
some hardware questions concerning the CoCo and various 
peripherals. Tandy Customer Service (817-624-1196) 

can assist in locating the nearest Tandy repair center, and 
possibly direct you to other services. 

One last note: don't expect a whole lot of assistance from 
Tandy. The CoCo is, after all, a discontinued machine, and 
Tandy NEVER offered a lot of support. Be reasonable in 
your expectations- don't expect miracles! The CoCo was 
always an underdog, misunderstood and mismarketed by its 
maker, especially in the final few years. 

2. Current User Groups (clubs) 

The following groups (clubs) were active as of February 
1993. National groups that publish newsletters at least four 
times per year are listed first. Local groups (those covering 
a small area only) are listed along with the last known point 
of contact. It is best to send a self addressed stamped 
envelope when requesting information to ensure a reply, or 
call. If calling, do consider the time and time zone (if in 
another). The local group list was compiled from listings on 
Delphi, the past two years (1991-92) of Rainbow magazine, 
and other reliable sources. Bear in mind that officers and 
points of contact are subject to change without notice. The 
listed individuals should be able to put you in contact with a 
current group member if they no longer belong to the group. 
Listing is in alphabetical order by state. 

National Groups 

NAME: Glenside Color Computer Club 
ADDRESS: 119 Adobe Circle 

Carpentersville, IL 60110-1101 
PHONE: 708-428-3576 
P.O.C: Tony Podraza 

also Carl Boll (CBJ on Delphi) 
RATES: $12 US (yearly) 

Glenside has been in existence almost as long as the CoCo 
itself (1981). They have members from across the US and 
Canada, though most are in the Chicago area. Meetings are 
held on the second Thursday of each month at the Glenside 
Public Library (25 W. Fullerton Avenue, Glendale Heights, 
IL). A newsletter (CoCo 123) averaging 10 pages is printed 
monthly. Note that the bylaws of the club only guarantee a 
quarterly publication. The newsletter is almost a magazine 
itself! The club supported BBS can be reached at 708-587- 
9837. An editorial, 2-3 articles, meeting overviews, occa- 
sional program listings, commercial ads, and member clas- 
sified ads are all provided free of additional charge. A 
newsletter exchange is conducted with other groups and 
clubs. Advertising vendors are asked, but not required, to 
give a membership discount in return for the advertising 
space. Most comply with a 10% discount. Glenside hosts the 

Tandy's Little Wonder 

page 51 

Annual "Last" Chicago CoCoFestyearly (usually in May), 
as it had done when Rainbow magazine promoted the 'fest. 
This is usually the largest CoCo event of the year. 

NAME: Mid Iowa & Country CoCo Club 
ADDRESS: 1328 48th Street 

Des Moines, lA 50311 
PHONE: 515-279-2576 

P.O.C: Terry Simons (MRUPGRADE on Delphi) 
RATES: $16 US, $21 Canada (yearly) 
MI&CCC has been in existence since 1984. The current 
publication is a disk based "newsletter" that has hi-resolution 
graphics and requires a CoCo 3 with one disk drive to run 
(minimum). Hard copies are available by special request. 
Supports a large public domain software library and an 
"orphanware" library (programs no longer supported by the 
writer or distributor, but not officially released as PD). The 
orphanware approach is unique to MI&CCC. They state that 
they will honor (remove from distribution) any request by a 
legitimate copyright holder or distributor with rights to a 
program(s) by removal from the library. Also supports a 
Christian Software sub-chapter that offers Christian ori- 
ented software and text files. Boasts membership in 24 
states and three Canadian provinces. Newsletter is published 
only October thru April and June. MI&CCC also sponsors 
the Mid America CoCoFest, Des Moines, lA, every year. 

NAME: OS-9 Users Group 
ADDRESS: P.O. Box 336 

Wyoming, DE 19934 
PHONE: 302-492-8511 
P.O.C: Jim DeStafeno (68xxx on Delphi) 
RATES: $25 US/Canada, $30 Foreign 
The new OS-9 Users Group sprang from the ashes of the old. 
The original fell apart sometime in 1991. It took only a few 
months for the remnants of the group to reorganize and form 
a new group in June of 1992. The library and newsletter 
(MOTD- Message of the Day- the name of the log-on 
message file in an OS-9 multi-user system) was passed from 
the old to the new group. Jim DeStafeno is the editor of 
MOTD, which is published bi-monthly. 

be arranged. The FIDO OS-9 Echo network is used for 
communication throughout the group. Over 400 0S-9/0SK 
users are listed as members of OCN. An alternate contact 
is Dave Kelly, 714 Garden Shadow Lane #5 1 , Arlington, TX 
77601, phone 817-795-9864 (OCN Region 19 Coordina- 
tor). A contact on Delphi is Tom Birt (user 0S9CN). 

Local Groups 

* Arizona - 

NAME: Tucson Color Computer Club 

PHONE: 602-298-7926 

P.O.C: Merle Metzger 

Meets the first Wednesday of every month, 7:00PM, at Finley 

DistributingCo., 2104 S.Euclid Ave. Tucson, AZ.AltemateP.O.C: 

Bruce Smith 602-747-7859 (before 8:00PM MST). Delphi contact: 


* CaUfornia - 

NAME: Citrus CoCo Club 

ADDRESS: P.O. Box 6991, San Bernardino, CA92412 

PHONE: 714-685-6334 

P.O.C: Orville Beaver 

NAME: Color America 

ADDRESS: 3811 N.FosterAvenue, Baldwin Park, CA91706 

PHONE: 818-960-8010 

P.O.C: JackEizenga 

NAME: Marysville/Yuba City Area CoCo Club 
ADDRESS: P.O. Box 5 1 26, Marysville, CA 9590 1 
PHONE: 916-742-5499 
P.O.C: Jim Vestal 

NAME: Sacramento CoCo Club 

ADDRESS: 2444 Wurth Court, Sacramento, CA 95825 

PHONE: 916-486-9665 

P.O.C: William Drennon 

Club supports a BBS at 916-486-1594 

NAME: StG Net West 

ADDRESS: P.O.Box38713, Hollywood, CA90038 

PHONE: 818-761-4135 

P.O.C: Alan Sheltra 

Club BBS (Zog's Cavern) number is 818-761-4721. Some DECB 

support, but mostly 0S-9/0SK. 

NAME: OS-9 Community Network 
ADDRESS: 2600 Wichita #9 

Pasadena, TX 77502 
PHONE: n/a 
P.O.C: Nancy Ward 
RATES: none 

The OS-9 Community Network (OCN) is really not a club 
nor a BBS network (see Networks). It is an organization 
complete with bylaws that supports 0S-9/0SK soft and hard 
ware. The network has regional network coordinators and 
libraries covering the U.S., Canada, and Australia. Software 
and articles are available via modem, though other means can 

* Colorado - 

NAME: Colorado Springs CoCo Club 

ADDRESS: 1118 Clairborne Road, Colorado Springs, CO 80906 

PHONE: 719-392-8268 

P.O.C: Bud Ward 

* Connecticut - 

NAME: Connecticut CoConut Connection 
ADDRESS: 2 Eagle Lane, Simsbury, CT 06070 
PHONE: 203-657-8373 
P.O.C: Charles Joseph Scanlon 

page 52 

Tandy's Little Wonder 

* Connecticut - 

NAME: South Eastern Connecticut Color Computer Users Group 


PHONE: 203-535-42 1 1 ; BBS 203-572-7649 

P.O.C: Larry Donovan 

Southeastern Connecticut area. Meets on the Third Tuesday of each 

month. Delphi contact: DOCTORDON 

* Florida - 

NAME: Cross County CoCo Club 
PHONE: 407-793-5658; BBS 407-433-3387 
Palm Beach County, Florida area. 

NAME: The CoCo 3 Users Group 
ADDRESS: 6042 Syrcle Ave., Milton, FL 32570 
PHONE: 904-623-4405 
P.O.C: Tom Batchelder 

* Kentucky - 

NAME: Hardin County CoCo Club 

ADDRESS: 2887 Republic Avenue, RadcUff, KY401 60 

PHONE: 502-351-4757 

P.O.C: PaulUrbahns 

* Louisiana - 

NAME: The CoCo Special Interest Group 
ADDRESS: 20 Gibbs Drive, Chalmette, LA 70043 
PHONE: 504-277-6880; BBS 504-277-5 1 35 
P.O.C: Christopher Mayeux 

* Maryland - 

NAME: Arkade 

ADDRESS: 35 13 Terrace Drive #D, Suifland, MD 20746 

PHONE: 301-423-8418 

P.O.C: John M. Beck 

* Georgia - 

NAME: Atlanta Computer Society, Inc. 

ADDRESS : 4290 Bells Ferry Road Ste. 1 0639, Kennesaw, GA 30 1 44 

PHONE: 404-469-5 111; BBS 404-636-299 1 

P.O.C: AlanDages 

Sponsors the annual Atlanta CoCoFest, first weekend in October. 

* Idaho - 

NAME: Snake River CoCo Club 

ADDRESS: 1 750 Camel Drive, Idaho Falls, ID 83403 

PHONE: 208-522-0220 

P.O.C: Emil Franklin 

* Illinois - 

NAME: Cook County CoCo Club 

ADDRESS: 10 McCarthy Lane, Park Forest, IL 60466-2122 

PHONE: 708-747-0117 

P.O.C: Howard Luckey 

NAME: Motorola Micro Computer Club 

ADDRESS: 1301 EastAlgonquinRd.,Shaumburg,IL 60196 

PHONE: 708-576-3044 

P.O.C: Steve Adler 

Supports all Motorola basedcomputers. 

NAME: Sterling CoCo Users Group A 
ADDRESS: 224 ParkDrive,SterUng,IL 6 108 1-3033 
PHONE: 815-626-7140 
P.O.C: Greg Adams 

* Iowa - 

NAME: Mid Iowa & Country CoCo 

ADDRESS: 1 328 48th Street, Des Moines, lA 503 1 1 

PHONE: 515-279-2576 

P.O.C. Terry Simons 

Local chapter of the national group. See national groups for details. 

* Iowa - 

NAME: Metro Area CoCo Club 
ADDRESS: 2425 Ave. A, Co. Bluffs, L\ 5 1 501 
PHONE: 712-322-2438 
P.O.C: JoeCavallaro 

* Massachusetts - 

NAME: NorthEast CoCo Club 

ADDRESS: 440 North Ave., Bldg.9#210,Haverhill,MA01830 

PHONE: 508-521-0164 

P.O.C: JoseJoubert 

* Michigan - 

NAME: Color Computer Owners Group 
ADDRESS: 388 EmmonsBlvd.,Wyandote, MI 48192 
PHONE: 313-283-2474 
P.O.C: Bernard A. Patton 

NAME: Greater Kalamazoo Color Computer Club 
Meets every third Wednesday of the month at 7:00pm in the Cross- 
roads Mall Community Room, Portage, MI. Delphi contact: user 

NAME: Greater Lansing CoCo Users Group 
ADDRESS: P.O. Box 14 1 1 4, Lansing, MI 4890 1 
PHONE: 517-626-6917 
P.O.C: DaleKnepper 

* Mississippi - 

NAME: Mississippi OS-9 Users Group 
ADDRESS: Box 8455, Hattiesburg, MS 39406-8455 
PHONE: 601-266-2807 
P.O.C: BoisyG.Pitre 

* Minnesota - 

NAME: Twin Cities CoCo Users Group 
PHONE: BBS 612-646-6693 (carries Internet list) 
Meets 2nd Tuesday, Hennepin County Government Center, 
6th Street, Minneapolis. 

* Missouri - 

NAME: CoCoNuts User Group 

ADDRESS: 2 1 1 6 N. Columbia, Springfield, MO 65803 

PHONE: 417-866-8738 

P.O.C: Clyde Loyd 

Tandy's Little Wonder 

page 53 

* Missouri - 

NAME: Kansas City CoCo 

ADDRESS: P.O. Box 520084, Independence, MO 64052 

PHONE: 913-764-9413 

P.O.C: Gay Crawford 

* Nebraslia - 

NAME: Metro Area CoCo Club 
ADDRESS: P.O. Box 3422, Omaha, NE 68103 
P.O.C: Bruce Gerst 

* New York - 

NAME: Adirondack CoCo Club 

ADDRESS: 10 RosewoodDrive, Clifton Park, NY 12065 

PHONE: 518-371-4781 

P.O.C: Thomas P. Delaney 

NAME: Erie County CoCo Club 

ADDRESS: 57 Chapel Avenue, Cheektowaga, NY 14225 

PP.O.C: John A. Lombardo 

NAME: Long Island CoCo Club 

ADDRESS: 103 Barbeny Lane, RoslynHeights,NY 11577 

P.O.C: Bill Rosenfeld ; RRIES on Delphi 

NAME: Twin Tiers CoCo Club 
ADDRESS : 3 1 9 Irvine Place, Ehnira, NY 1 490 1 
PHONE: 607-734-0065 
P.O.C . : William Cecchini 

* Nortli Carolina - 

NAME: Norca Users Group 

ADDRESS: 1601 Rogers Drive, Fayetteville,NC 28303 

PHONE: 919-484-1230 

Membership is FREE to everyone in the Greater Fayetteville-Fort 

Bragg area; long-distance users are encouraged to become members 

of Norca Gold, for $15.00 a year (a newsletter is sent). Club BBS 

numbers: 9 1 9-868-843 1 or 9 1 9-867-7 1 52, 24 hours. Delphi contact: 


NAME: Raleigh CoCo Club 

ADDRESS: P.O. Box 1 0632, Raleigh, NC 27605 

PHONE: 919-878-3865 

* Ohio - 

NAME: Dayton Area CoCo Users Group 
ADDRESS: 308 Orangewood Drive, Kettering, OH 45429 
PHONE: 513-434-9168 
P.O.C: John Teague 

NAME: Greater Toledo CoCo Club 

ADDRESS: 1319North St., BowlingGreen, OH 43402 

PHONE: 419-471-9444 

P.O.C: BillEspen 

NAME: Tri-County Computer Users Group 
ADDRESS: 109 14 Oliver Road, Cleveland, OH 441 1 1 
PHONE: 216-476-2687 
P.O.C: Ron Potter 

* Pennsylvania - 

NAME: The Penn Jersey Color Computer Club 
Meets last Friday of each month. Monthly newsletter. The 6809 
Express. Club BBS, 215-760-0456. Located in the AUentown/ 
Bethlehem area. Associate memberships available for those who 
can't attend the meetings. Delphi contact: user ALWAGNER 

NAME: Cumberland Valley Users Group 
ADDRESS: 9085 Newburg Road, Newburg, PA 17240 
PHONE: 717-423-5525 
P.O.C: Thomas Martin -9 

NAME: Johnstown Area CoCo Users Group 
ADDRESS: 1 1 1 C St., Apt. #1, Johnstown, PA 15906 
PHONE: 814-535-1497 
P.O.C: Albert Baldish 

NAME: Pittsburgh Color Group 

ADDRESS: 309 FrazierDrive, Pittsburgh, PA 15235 

PHONE: 412-823-7607 

P.O.C: Ralph Marting 

* Puerto Rico 

NAME: Puerto Rico CoCo Club 

ADDRESS: P.O. Box2072,Guaynabo,PR 00657-7004 

PHONE: 809-799-8217or809-728-2314 

P.O.C: Luis R. Martinez 

NAME: The Tandy CoCo Users of Charlotte 
ADDRESS: 1 022 Noles Drive, Mt. Holly, NC 28 1 20 
P.O.C: Eric Stringer 

* Ohio - 

NAME: Columbus CoCo Club 

ADDRESS: 6855GreenleafBlvd.,AptB-2,Reynoldsburg,OH43068 

P.O.C: Steven P. Taulborg 

Meetings held in the Chemical Abstracts building on OUentangy River 

RD near Lane Ave. They are held on the THIRD MONDAY of each 

month at 7:30 PM. Delphi contact: user TAULBORG. 

* Rhode Island - 

NAME: New England CoCoNuts 

ADDRESS: P.O. Box 28 1 06 North Station, Providence, RI 02908 

PHONE: 401-272-5096 

P.O.C: Arthur J. Mendonca 

* South CaroUna - 

NAME: Spartanburg CoCo Club 

ADDRESS: 1 52 Bon Air Avenue, Spartanburg, SC 29303 

PHONE: 803-573-9881 

P.O.C: Jesse W. Parris 

NAME: Columbus & Central Ohio CoCo Club 
ADDRESS: 546 Woodside Drive S.W., Pataskala, OH 43062 
PHONE: 614-927-3357 
P.O.C: Richard Heber 

* South Dakota - 

NAME: Empire Area CoCo Users Group 
ADDRESS: P.O. Box 395, Brandon, SD 57005 
PHONE: 605-582-3862 
P.O.C: Carl Holt 

page 54 

Tandy's Little Wonder 

* Texas - 

NAME: CoCoNauts 

ADDRESS: 1 62 1 8 Brinkwood Drive, Houston, TX 77090 

PHONE: 713-580-6420 

P.O.C: Arthur J. Volz 

NAME: Codis CoCo Symphony 

ADDRESS: 2902 Harvard Street, Irving, TX 75062 

PHONE: 214-570-0823 

P.O.C: William C.Garretson 

International User Groups (local to their area) 

NAME: Australian National OS-9 Users Group 
ADDRESS : C/-8 Odin Street, SunnybanJc, Queensland, 4 1 09 
PHONE: 07-344-3881 
P.O.C: Gordon Bentzen 

NAME: Brisbane Southwest CoCo Users Group 
ADDRESS : 2 1 Virgo Street, Inala, Queensland, 4077 
PHONE: 07-372-7816 
P.O.C: BobDevries 

NAME: Mid Cities TRS-80 Users Group 
ADDRESS: P.O.Box 171566, Arlington, TX76003 
PHONE: 817-535-7931 

* Utah - 

NAME: Salt City CoCo Club 

ADDRESS: 6357 S. Lotus Way, West Jordan, UT 84084 

PHONE: 801-968-8668 

P.O.C: L. Todd Knudsen 

* Virginia - 

NAME: Richmond Area CoCo Organization 
ADDRESS: 6003 Westboume Drive, Richmond, VA 23230 
PHONE: 804-282-7778 
P.O.C: WilliamT. Mays 

NAME: Southwestern Virginia CoCo Club 
ADDRESS: Route 1 Box 20, Henry, VA 24102 
PHONE: 703-365-2018 
P.O.C: Ricky Sutphin 

* Washington - 

NAME: Bellingham OS-9 Users Group 
ADDRESS: 3404 Illinois Lane, Bellingham, WA98226 
PHONE: 206-734-5806 
P.O.C: Rodger Alexander 

NAME: Port O' CoCo 

ADDRESS: 3046 Banner Road SE, Port Orchard, WA 98366-8810 

PHONE: 206-871-6535 

P.O.C: Donald Zimmerman 

Sponsors Pacific Northwest CoCoFest. 

NAME: Spokane CoCo Club 

ADDRESS: W. 221 7 Sanson, Spokane, WA 99205 

PHONE: 509-326-2793 

P.O.C: Richard Baysinger 

Club supports a BBS at 509-325-6787. 

* West Virginia - 

NAME: Huntington Area CoCo Symposium 
ADDRESS: P.O. Box 391, Lesage, WV 25537-0391 
PHONE: 304-736-5314 
P.O.C: Jim Bush 


NAME: Belgian OS-9 users Group 
ADDRESS: Kasteelplein72/9 


NAME: Club d'Oridinateur Couleur du Quebec Inc. 
ADDRESS: 8000 Metropolitan, est Anjou.QuebecHlK lAl 
PHONE: 514-354-4941 

NAME: Edmonton CoCo Users Group 

ADDRESS: 13208-128 Avenue, Edmonton, Alberta T5L3H2 

PHONE: 403-426-1888 

P.O.C: LloydFolden 

NAME: Moncton-Dieppe-Riverview CoCo Club 
ADDRESS: 77 Ninth Street, Moncton, New Brunswick E 1 E 3E5 
PHONE: 506-382-7706 
P.O.C: Philippe Lantin 

NAME: Motorola Users Group of London 
ADDRESS : RR# 1 Miller Road, Delaware, Ontario NOL 1 EO 
PHONE:519-652-3844(ClubBBS519-264-9063,8Nl, 300-2400) 
P.O.C: Gerard Gubbels 

NAME: Vancouver CoCo Club (VC3) 
PHONE: 604-420-6081 
P.O.C: JordanJ. Dobrikin 


NAME: OS-9 Users Group in Europe 
ADDRESS: LeipzigerRing22A,D-5042 Erfstadt 
PHONE: +49-2235-41069 
P.O.C: BurghardKinzel 

GreatBritain (Englandfor U.S. folks!) 

NAME: OS-9 Users Group 

ADDRESS : 23 Bristol Avenue, Levenshulme, Manchester M 1 9 3NU 


NAME: OS-9 User Group Japan 

ADDRESS: P.O.Box29Isehara,Kanagawa259-ll 

P.O.C: ChikaraYamaguchi 

Internet Address: 

The Netherlands 

NAME: European OS-9 UserGroup 

ADDRESS: Strijperstraat 50A, 5595 GD Leende 

PHONE: +31-4906-1971 

P.O.C: Peter Tutelaers 

Internet Address: 

Norway (& Scandinavian Countries) 
NAME: Norwegian OS-9 Users Group 
ADDRESS: SandvedTerrasse 29, 4300 Sandnes 
P.O.C: John Perry 

Tandy's Little Wonder 

page 55 

3. Current Vendors 

The listed vendors were known to support the Color Computer and 
OS-9/68000 (OSK) machines as of February 1 993 . Some still adver- 
tise, others no longer advertise but still answer requests for information 
and orders. All the display ads at the end of the listing were paid for, 
so these are the best bets. If one is unable to check advertising sources 
it is best to send a self addressed, stamped envelope (SASE) to a 
vendor requesting infomiation. Do not expect a speedy reply unless 
this is done. When calling, do remember that there are different time 
zones! Most vendors operate part-time and accept calls up to 9pm 
(THEIR TIME, not necessarily yours! ), though some will have to be 
called during regular business hours. 

NAME: BlackHawk Enterprises 

ADDRESS: P.O. Box 10552, Enid, OK 73706-0552 

PHONE: 405-234-2347 

MM/ 1 dealer. Large list of commercial and public domain software for 


NAME: Bob van der Poel Software 

ADDRESS: P.O. Box 355, Wynndel, BC VOB 2N0, CANADA or 

P.O. Box 57, Porthill, ID 83853, US 

PHONE: 604-866-5772 

Various titles. Most popular products are VED text editor and 

VPRINT text fomatter, both for OS-9 and/or OSK. 

NAME: Burke&Burke 

ADDRESS: P.O. Box 733, Maple Valley, WA 98038 

PHONE: 800-237-2409(orders),206-432-1814(tech&info) 

Hard drive adapter, software, & PowerBoost, an HD63B09Eproces- 

sor and patches for OS-9. Also various OS-9 utilities and games. 

NAME: Canaware 

ADDRESS: 1378 Credit Woodlands Ct., Mississauga, Ontario 


PHONE: 416-279-4395 

Various titles. Custom programming. Delphi User DONVAIL. 

NAME: Cer-CompLtd. 

ADDRESS: 5566 Ricochet Ave., Las Vegas, NV 891 10 

PHONE: 702-452-0632 

BASIC Compiler, A/L programming utilities, DECB windowing 

software (word peocessor, memory resident utils., etc.) 

NAME: Coless Computer Design 

ADDRESS: 1917 Madera St. #8, Waukesha, WI 53186 

Sells cm Pages, a good desktop publishing package for the CoCo 3 . 

NAME: Color Computing Software 

ADDRESS: 65 Oak Road, Canton, MA 02021 

PHONE: 617-828-7749 

Various titles. Former publisher of TRS-80 Computing Magazine. 

Two disk set of magazine programs available. Back issues available. 

NAME: Color Systems 

ADDRESS: P.O. Box 540, Castle Hayne, NC 28429 

PHONE: 919-675-1706 

Various titles. OSK support primarily for MM/1 . 

NAME: Computer Plus 

ADDRESS: P.O.Box 1094, 480 King Street, Littleton, MA 01 460 

PHONE: 1-800-343-8124(508-486-3193 in MA) 

Long-time discount Tandy dealer. Various Tandy soft/hardware. 

NAME: Dayton Associates, Inc. 

ADDRESS: 9644 QuailwoodTrail,Spring Valley, OH45370 

PHONE: 513-885-5999 

Printers and serial to parallel convertors (interface). 

NAME: Dirt Cheap Computer Stuff Company 

ADDRESS: 1368 OldHwy 50 East, Union, MO 63034 
Various OS-9 & OSK titles (mostly OSK) 

NAME: Eversoft Games, Ltd. 
ADDRESS: P.O. Box 3354, Arlington, WA 98223 
PHONE: 206-653-5263 
Various game titles. 

NAME: FARNA Systems 

ADDRESS: 904 2nd Avenue, Warner Robins, GA 3 1 098- 1 029 
PHONE: 912-328-7859 

Various DECB/OS-9 software, books . Publisherof "the worldof 68' 
micros" magazine. 

NAME: Granite Computer Systems 

ADDRESS: 571 Center Road, Hillsborough, NH03244 

PHONE: 603-464-3850 

Modems, OS-9/ OSK software. File utility that transfers files 

between OS-9/OSK/MS-DOS. Runs on CoCo 1-3, OSKmachines. 

NAME: HardSoft 

ADDRESS: 26 Alfred St., Napanee, Ontario K7R 3H7, CANADA 

PHONE: 613-354-5734 

SCSI hard disk driver (5 12 byte sectors!) for all CoCo adapters. 

NAME: Hawksoft 

ADDRESS: P.O.Box71 12, Elgin, IL 60121-71 12 

PHONE: 708-742-3084 

Hardware and various OS-9/DECB software. 

NAME: Infinitum Technology 

ADDRESS: P.O. Box 356, Saddle River, NJ 07458 

PHONE: 914-356-7688 

"C" programming language package for CoCo 2 or 3 (DECB). 

NAME: JWT Enterprises 

ADDRESS: 5755 LockwoodBlvd.,Youngstown, OH 44512 
PHONE: 216-758-7694 

OS-9 utility software. Publisherof "Nine-Times" OS-9 disk magazine 
and "UpTime" advertising newsletter (DECB, OS-9, & OSK). 

NAME: Kala Software 

ADDRESS: 3801 Brown Bark Drive, Greensboro, NC 274 10 

PHONE: 919-294-1558 

MIDI music notation editorforCoCo(UltiMusE&UltiMusEIII) and 

OSK (UltiMusE/K). Music disks forplayback available. 

NAME: MediaLink Software 

ADDRESS: 4855 Vegas Vally Blvd. 17 Ste. 145, Las Vegas, NV 


Disk BASIC games, utihties, etc. Delphi contact CHETSIMPSON 

NAME: Owl-Ware 

ADDRESS: P.O. Box 1 16, Mertztown, PA 19539 

PHONE: 800-245-6228 (orders) 2 1 5-837- 1 9 1 7 (tech, info) 

Hard & floppy drives, 5 1 2K upgrades, some DECB & OS-9 software. 

page 56 

Tandy's Little Wonder 

NAME: Rick's Computer Enterprise 

ADDRESS: P.O. Box 276, Liberty, KY 42539 

PHONE: 606-787-5783 

Several DECB & OS-9 tittles,bought license for fomer CoCoPRO! 

software. Publisher of CoCo Friends disk magazine. 

NAME: Spectro Systems 

ADDRESS: 11111 N.Kendall Dr. Suite A108,Miami,FL 33176 

PHONE: 305-274-3899 

Primary product is ADOS, a DECB enhancer for all CoCo models. 

Can be EPROMed. THE most popular enhancement for all CoCos. 

NAME: Strongware 

ADDRESS: Box 361, Matthews, IN 46957 

CoCo 3 games, font editor, fonts; MM/1 graphics tools, more. 

NAME: Sundog Systems 

ADDRESS: P.O. Box 766, Manassas, VA 221 1 1 

PHONE: 703-330-8989 

Largest selection of games for the CoCo. High quality graphics and 

sound. Some for CoCo 1-3, many require CoCo 3. and 5 12K. 

NAME: T&D Software 

ADDRESS: 2490 Miles Standish Dr., Holland, MI 49424 

PHONE: 6 1 6-399-9648, FAX 6 1 6-396-2744 

Large assortment of DECB programs, many PD and share- ware. 

4. Current Annual CoCo Shows 

1. Atlanta CoCoFest (GEORGIA) Beginning with the 
Oct. 3-4, 1992 fest, Atlanta CoCoFest was sponsored en- 
tirely by the Atlanta Computer Society, Inc., the local CoCo 
organization. It is held the first weekend in October. For 
more information contact Alan Dages (404-469-5111) or 
the club BBS at 404-636-2991. Atlanta Computer Society, 
hic. 4290 Bells Ferry Road Suite 10639, Kennesaw, GA 
30144. This was the first regional 'fest sponsored by a club 
or vendor and not a magazine. 

2. Chicago CoCoFest (ILLINOIS) Glenside CoCo Club 
picked up sponsorship of the Chicago event beginning in 
May of 1993. It is to be held the first weekend of May. 
Contact Tony Podraza (708-428-3576) or the club BBS at 
708-587-9837. Glenside Color Computer Club 119 Adobe 
Circle, Carpentersville, IL 60110-1101. 

3. Pacific Northwest CoCoFest (WASHINGTON) This 
event is held in June at Port Orchard, WA, sponsored by Port 
O' CoCo Users Group. The first was held in 1992. Contact 
is Donald Zimmerman (206-871-6535). Port O' CoCo 
Users Group 3046 Banner Road SE, Port Orchard, WA 

4. Middle America CoCoFest (IOWA) Sponsored by Mid 
Iowa/Country CoCo Club, first held in April 1993, Des 
Moines, lA. Plan on going every year! Contact is Terry 
Simons (515-279-2576). Mid Iowa & Country CoCo Club 
1328 48th Street, Des Moines, lA 50311. 

5. Telecommunications 

For remote users, or anyone who has no local users group, 
I have only one thing to say: GET A MODEM! Telecommu- 
nications is any form of communication extended over 
telephone lines. Most often it refers to just one thing: 
computers communicating with other computers, and of 
course, there are users behind those keyboards! If you have 
a telephone, another CoCo user- actually THOUSANDS of 
CoCo users- are just a phone call away. 

A modem allows signals generated by a computer to be 
transmitted over regular phone lines. Phone lines are de- 
signed to carry only certain frequencies, and computers 
generate signals that are not normally within this range. 
Therefore, the signals must be modulated (frequency 
changed) to a signal that can be carried by the phone lines, 
then demodulated (changed back to their original state). A 
modem is simply a modulator/ demodulator and performs 
this frequency change in either direction, depending on 
whether it was set to originate (send) or receive the signal. 
Most modern modems are switched between send and re- 
ceive modes by software or a keyboard command, but some 
older models will have an originate/receive switch on them. 
For the most part, a modem is used to originate the call to a 
bulletin board system (BBS) where other users can be 

One can usually find a BBS locally, or there is a local access 
number for at least one large, national BBS. A BBS in its 
simplest form is nothing more than another computer con- 
nected to a phone line with a modem in answer mode. Special 
software is run on the BBS computer that allows callers to 
leave messages, upload/download (transfer from the calling 
computer to the BBS/ vice-versa) files and programs, and in 
most cases even play games against another opponent or the 
computer. There are often several specialized message 
areas, called SIGs (special interest groups) or forums, that 
cover single (or commonly grouped together) topics. These 
may be for different types of computers (such as the CoCo, 
Commodore, Apple, PC, etc. SIGs on Delphi) or any subject 
the BBS operator and users are interested in. 

What does one need to know to get started? First of all, get 
a modem! Almost any external modem will work with a 
CoCo. If all one is interested in is leaving and reading 
messages, a 300 bps model will get one started. For up/down 
loading, 1200 bps is the minimum recommended. A CoCo 2 
will work with up to a 1200 bps modem with no additional 
equipment, a CoCo 3 up to 2400 bps. Faster rates than these 
will require an RS-232 Pak or equivalent (see peripherals). 
If using OS-9, an RS-232 Pak is necessary for all but reliable 
300 bps operation. 

Just what is a "bps"? The term refers to "bits per second" and 
is the number of bits (ones or zeros in computer language) 
a modem can transfer in one second. The larger the number, 
the faster the transfer rate. A 300 bps modem will up/ 

Tandy's Little Wonder 

page 57 

download files, but will tale a very long time even for small 
files. Some BBS systems don't even support 300 bps opera- 
tion, while others just lock out up/down load capabilities for 
300 bps callers. This is a courtesy to other users, as many 
systems only have one phone line, and a 300 bps user 
transferring a long file would tie up the system for quite a 

Some people erroneously refer to modem speed as "baud". 
Baud (short for "Baudot"- the name of a Frenchman who 
designed the French telegraph codes) refers to the maxi- 
mum number of electrical changes per second (changes 
between "on" and "off) that can occur over a communica- 
tions circuit. In the early days of computing, a change had to 
occur in order to transfer one bit, thus 300-600 baud mo- 
dems actually transmitted data at 300-600 bits per second. 
As modems evolved, the number of bits that could be sent per 
second overcame the baud rate limitation. 1200 bps mo- 
dems actually transmit at 600 baud, 9600 bps modems at 
2400 baud. 

The most common CoCo telecommunications programs 
will only handle up to 2400 bps operation, though some will 
allow up to 9600. Very few CoCo owners own modems over 
2400 bps (at least not connected to their CoCos). The Tandy 
DCM Modem Pak contains rudimentary software built in, 
but this is only good for message reading, not up/down loads. 
The ROM chip should be disabled for use with a Y cable and 
disk controller. Disable the chip by cutting the leg to the 
right of the notch in the chip (viewing with the notch at the 
"top"... this pin supplies power to the ROM). 

The most recommended share-ware programs are: Mickey- 
Term (can be used with tape based systems) Greg-E-Term 
(CoCo 2 or 3, 32-80 column screen support) UltimaTerm 
(CoCo 3 only, many features) and SuperComm (OS-9 
terminal program). These are available for download from 
Delphi and purchase from FARNA Systems and T&D Soft- 
ware. Remember, if purchasing share -ware from a vendor, 
one should still attempt to send the author a registration fee 
or donation for the writing the program. These programs all 
support RS-232 paks. Greg-E-Term and Mickey-Term also 
support the DC Modem Pak. There are also many commer- 
cial programs available from various vendors. 

Hmmm.... the CoCo doesn't have a modem port, and the 
connector on the modem has 25 pins, so where does it plug 
in? Modems are serial devices, meaning they transmit one 
bit at a time, one after the other. Well, the "serial I/O" plug 
on the back of the CoCo has only four pins! A cable must be 
made. All the components are available at most Radio Shack 
stores. Cables are pretty easy to make, especially if one isn't 
scared to warm up a soldering iron. Simply connect the wires 
on the CoCo four pin plug to those listed for the 25 pin 
connector (DB-25): 

CoCo 4 pin DB-25 



2 3 

3 7 

4 2 (All other lines unconnected) 
Pin (CoCo/DB-25): Function 

1/8: Carrier Detect 
2/3 : Receive Data 
3/7: Signal Ground 
4/2: Transmit Data 
/4: Request to Send 
16: Data Set Ready 
/20: Data Terminal Ready 
* Refer to modem manual for switch settings. By tieing lines 
4, 6, and/or 20 to 8 (CD), they are set "high" when the modem 
is in operation. Switch setup modems have switches to set 
these lines high, eliminating the need to connect them to the 
CD signal. 

Note that the CoCo 1/2 is only capable of reliable 1200 bps 
operation from the built in serial port. This port isn't a true 
serial port at all- it uses a PIA and software to simulate the 
workings of an RS-232 port. The CoCo 3 is capable of 2400 
bps due to design improvements in the RS-232 hard/soft 
ware. The RS-232 Pak has a special chip (called a UART) 
which does this in place of the CoCo's built in software. 

An RS-232 Pak or equivalent has a standard DB-25 connec- 
tor. With this, a standard modem cable should work unal- 
tered. All the RS-232 paks produced for the CoCo work and 
are addressed as the Tandy pak. The single exception to this 
is the Disto add-on RS-232 ports that mount into the Super 
(disk) Controllers. That Disto port is usable only by OS-9, 
where the address can be easily changed. The stand-alone 
Disto pak is addressed the same as the Tandy. The only 
current manufacturer of RS-232 paks is CoNect. CoCoPRO ! 
sold a converted DC Modem pak (also a kit) that was just as 
good for modem use, and works like the other paks. Some 
problems may be experienced with the CoCoPRO ! conver- 
sion when connecting to terminals under OS-9. This conver- 
sion was also described in a Rainbow article by Marty 
Goodman. An RS-232 Pak must be used for speeds higher 
than 1200 for a CoCo 1 or 2, 2400 for a CoCo 3 when using 

OS-9 generally requires an RS-232 Pak because the CoCo's 
software needs a lot of monitoring by the CPU, which 
performs functions of the UART. This monitoring reduces 
creates a special software driver that will allow OS-9 to use 
the serial port, but it is not reliable over 300 bps. Unless one 
is very familiar with OS-9, this method should NOT be used. 

page 58 

Tandy's Little Wonder 

National Bulletin Board/Database Systems 

There are generally two types of BBSs: national and local. 
National refers to large commercial systems offering a wide 
variety of information over many different subjects. On 
these one can do everything from finding a bit of software 
and information about on's computer to booking flights on 
major airlines. Most metropolitan areas have local access 
numbers so that no long distance calls are required. These 
systems are toll systems, however, requiring an hourly or 
monthly fee. Hourly rates average $8 per hour, but the 
monthly rates are as low as $5 for limited access. There are 
three of interest to CoCo users (they have large CoCo SIGs 
available... toll free numbers listed are for voice informa- 

Computer Information Services (CompuServe) 

RATES: $12.80/hr AND $7.95/month; 1-800-848-8199 
CompuServe is the oldest, largest computer information 
system in the U.S., and is often referred to as "CIS" (or "CIS", 
due to their higher rates). "Basic" services (electronic mail, 
encyclopedia, some general message bases) are free under 
the monthly payment. The monthly fee does not include the 
computer forums or many other "premium" services, such as 
travel information, which is billed at the hourly rate. Rates 
are significantly higher than the other services, but there is 
usually more message traffic and files available. The first 
CoCo SIG was created on CompuServe in June 1982. The 
listed hourly rate is for 1200/2400 bps access. Faster 
modems are charged more, slower less (slower modems 
mean longer connect time!). 

General Videotex Corporation (Delplii) 

RATES: $5.95/hr OR $20.00/month; 1-800-695-4005 
Delphi's "20/20" plan offers 20 hours use for $20 monthly, 
additional hours over 20 charged at only $1.40/hr. Requires 
one-time $19 registration fee. All services accessible using 
"20/20". No modem speed restrictions. Note that Falsoft, 
publisher of now defunct "The Rainbow" magazine, contin- 
ues to sponsor the CoCo and OS-9 SIGs (and also the PC 
SIG) on Delphi, and can be contacted there. If one has a 
subscription PCM, membership and one hour connect time 
is free. Contact Delphi or Falsoft for further information. 
The publisher of "the world of 68' micros" also frequents 
Delphi (DSRTFOX) and can be contacted there. 

General Electric Network (GENie) 

RATES: $6.00/hr AND $4.95/month; 1-800-638-9636 
GENie is the lowest cost network for the occasional user. 
The GENie rate structure is similar to that of CompuServe, 
with free access to "basic" services and pay access to "pre- 
mium" services. Hourly fees slightly higher for modems 
faster than 2400 bps. The prime attraction for the occasional 
user is the low monthly and hourly fees. It should be noted 
that GENie was the first to use this type billing system, the 
CompuServe system was patterned after GENie. The CoCo 
is covered in the Tandy area. 

Local Bulletin Board Systems 

Local BBSs can naturally be reached from any phone across 
the country or even world wide. They are typically regionally 
or locally oriented though, and are smaller in scope than the 
major national systems. Note that many boards support 
other computer types as well as the CoCo/OSK machines. 
Most of these boards are set up as a hobby, totally out of the 
operators expense. Some ask for donations or "user fees" to 
help defray the cost of running a board, while others are 
totally free to use. Don't be upset if the board goes down with 
no notice. If a board is no longer in service, please pick up the 
phone if someone answers! Explain what you were trying to 
do, apologize if the board is no longer in service, and spread 
the word. The person answering will appreciate it! Many 
times they do not know that the weird sound in the phone is 
a computer, and think they are being harassed. If the answerer 
gets irate merely hang up! You might be angry if you 
answered the phone many times only to hear a strange, high 
pitched tone in your ear! Please let other BBS callers know 
the BBS is no longer at that number as a courtesy to the 
person on the other end of the phone. 

Settings of 8 bits, no parity, and 1 stop bit (8-N-l) are 
assumed. Only the HIGHEST baud rate is listed, lower rates 
are also supported from 300 up unless otherwise noted. 
Listing is in numerical order by area code, then alphabetic by 
name. Network support is under the NETWORKS heading. 
Canadian boards are also listed. This is only a small listing... 
more numbers will usually be found on the boards. 

Even if there isn't a listing for a local board, call the nearest 
to your area and look for other numbers. If you must call long 
distance, it is usually cheaper to call another state rather than 
one in your phone company ' s area due to competition among 
long distance carriers. This is especially true if one sub- 
scribes to a long distance savings plan such as Reach Out 
America (AT&T). Night and evening rates are cheaper also- 
most BBSs can be called at any hour! While this may limit 
access to an hour or two monthly, one can still check out 
news and get help fast. 

Don't forget to check the club listings, as many clubs also 
support a BBS. Also, don't be afraid to leave messages on 
boards that support other systems. While a little good 
natured harassment may come with letting others (who all 
believe they have superior systems., sort of like Ford and 
Chevy car lovers!) know you use a CoCo, one may also find 
another lonely CoConut! 

Name / Phone / Hours / Baud / Network 

RCISHQ/ 201-967-1061/ 24/ 2400 /RCIS 

IMS (MM/1 manufacturer)/ 202-232-4246 / 6p-6a / 2400 / FIDO 

Applause / 203-754-9598 / 24 / 2400 

Pink Rose / 203-738-3064 / 24 / 2400 

Silk City / 203-649-9057 / 24 / 2400 

Access CoCo of LA/ 205-598-2100 / 24 / 2400 / FIDO 

CoCo Plus / 205-341-1616 / 24 / 2400 / FIDO 

Norm'sPlace / 205-661-5298/ 24/ 2400 / FIDO 

Tandy's Little Wonder 

page 59 

Name / Phone / Hours / Baud / Network 

Columbia Heights / 206-425-5804/ 24 / 2400 / FIDO 
OS-9Tacoma / 206-566-8857 / 24 / 2400 / FIDO 
Ultimate Experience / 206-299-0491 / 24 / 1200 / FIDO 
DownEaster/ 207-725-8035/ 24/ 1200 / FIDO 
Snake River / 208-523-3796/24 / 1200 
Zog'sCavem / 213-461-7948/24 / 2400 
CoCoZone / 214-553-1649/24/ 1200 / FIDO 
Charlie'sHelpLine/ 215-825-3226/ 24 / 1200 
Exotic Zone / 301-969-3083/ 24 / 2400/ FIDO 
Federal Hill / 301-685-6975/24 / 2400 /FIDO 
C.T.V. / 303-321-0356/ llp-8a / 2400 / FIDO 
BlueParrotCafe/ 303-757-6197/ 24 / 2400 / FIDO 
Mustang Professional / 306-978-1962 / 24 / 2400/ FIDO 
J&L-sCoCoComer/ 313-292-4713 / 24 / 2400 
Kansas Konnektion/ 316-342-3967/24 / 2400/ FIDO 
Weather Connection/ 401-728-8709/24 / 2400 
Heart of Gold / 403-437-3864/24 / 2400 / FIDO 
Photo Net / 403-425-6249/24 / 2400/ StG 
So.Alberta Bulletin/ 403-329-6438/ 24 / 2400/ StG 
ACCUG / 404-465-2977 / 24 / 2400 / FIDO 
Hayes / 404-446-6336 / 24 / 9600 
Arrakis / 405-752-8955 / 24 / 2400 /FIDO 
PatBBS / 405-598-5082/ 5p-9p(10a-10pwknds)/ 300 
Tomcat's BBS / 405-282-8250/ 24 / 2400 / FIDO 
Applied OS-9 / 407-327-6346 /24 / 2400 / FIDO 
CoCoZone / 407-433-3387 /24 / 2400 / FIDO 
KB Enterprises / 407-799-3282 / 5p-9a / 1200 
CoCo Workshop / 413-593-3944 / 24 / 2400 / FIDO 
SunBBS/ 413-447-2346/24/ 2400/ FIDO 
PackerCityRiBBS/ 414-496-1680 / 24 / 2400 /FIDO 
Rocky's Data Squash / 414-684-4115 / 24 / 2400/ FIDO 
ColorGalaxy / 415-883-0696 / 24 / 2400 /RCIS 
House ofFire / 416-601-0085 / 24 / 2400 /FIDO 
TCCCBBS / 416-288-6084 / 24 / 2400/ FIDO 
Score Board /417-887-6076 / 24 / 2400 / FIDO 
8-Bit Wonderland / 501-931-9528 / 24 / 2400 
Grant County BBS/ 501-942-4047/24 / 2400 
Big Easy / 504-464-0289 / 24 / 2400 / FIDO 
Node III / 504-347-4320 / 24 / 2400 / FIDO 
Gosub / 508-756-1442 / 24 / 2400 
Graveyard / 508-792-0381 / 24 / 2400 / FIDO 
Data Warehouse / 509-325-6787 / 24 / 2400 / FIDO 
DiamondMine / 509-325-5160 / 24 / 2400 / FIDO 
Dog House / 509-325-3169 / 24 / 2400 / FIDO 
Indulgence / 509-482-0455 / FriPM-SunPM / 2400 / FIDO 
Trial Run / 512-280-6578 / 24 / 2400 / FIDO 
L'Equipe / 514-325-0659 / 24 / 2400 / FIDO 
InfoLink(OS-9UG) / 5 15-987-53 15 / 24 / 2400 / StG 
Benchboard / 517-394-2447 /24/ 2400 / FIDO 
Color Connection / 519-948-1879 / 24 / 1200 
MidNightRiBBS / 519-457-3737 / 24/ 2400 / FIDO 
OS-9 Zone / 601-266-2807 / 10p-6a / 2400 
Kzin / 604-589-1660 / 24 / 2400/ StG 
Kzin / 604-589-5545 / 24 / 2400 / FIDO 
Pot '0 Gold / 604-564-8869 / 24 / 2400 / FIDO 
Science Fiction / 604-944-6390 / 24 / 2400 / StG 
Cross-N-Crown / 606-754-9420 / 24 / 2400 
George's Dewdrop Inn / 606-356-1431 / 24 / 2400 / FIDO 
BB's Place / 612-869-7752/ 24/ 2400 / FIDO 
Eighty Megz / 612-777-4193 / 24 / 2400 / FIDO 
East Side / 614-755-2492 / 24 / 2400 
Springwood / 614-228-7371 / 24 / 2400 / FIDO 
Crystal Palace/ 616-723-0146/ 24/ 2400 
Byte Box / 619-277-4618 / 24 / 2400 / FIDO 
Cajin'sKeep / 619-280-3691 / 24 / 2400 / FIDO 
CoCo Exchange / 619-272-3643 / 24 / 2400 / FIDO 
FourC's / 619-936-0823 / 24 / 2400 / FIDO 
Ocean Beach / 619-224-4878 / 24 / 2400 / FIDO 
Nine-Line / 701-727-6826 / 24 / 1200 
Clem'sComer / 703-322-4053/ 6p-llp/ 1200 

Name / Phone / Hours / Baud / Network 

Stargate / 704-788-7867 / 24 / 2400 

Cup of CoCo / 708-428-0436 / 24 / 2400/ FIDO 

Pinball Haven/ 708-428-8445/24 / 2400 

S&V / 708-352-0948 /24 / 2400 / StG 

ColorNET/ 709-884-2176/24 / 300 

MACCC / 712-366-5252/ 24 / 2400 / FIDO 

Golden CoCo / 713-941-1542 / 24 / 2400/ FIDO 

Cassie'sComer / 714-841-0116 /24 / 2400 / AcBBS 

Rainbow Connection / 714-831-6530 / 24 / 2400 / RCIS 

Delta Systems / 716-494-2520 / 24/ 2400 / FIDO 

Erie County / 716-649-1368 / 24 / 2400 

Citadel / 717-393-5195 / 24 / 2400 / FIDO 

Time Safari / 719-635-7228 / 24 / 1200 

Thermal Fusion / 803-967-9832 / 24 / 2400 / FIDO 

Tree House / 804-744-0157 / 24 / 2400 

CoCoNuts / 808-845-7054 /24 / 2400 

CoCo Library / 808-845-5299 / 24 / 2400 / FIDO 

Download Syndrome /813-367-1285 / 24 / 2400 / FIDO 

CoCo Electronic / 814-535-1497 / 8p-6a / 2400 

Galactic / 814-535-1497 / 24 / 2400 / FIDO 

Evening Edition/ 816-429-5741 / 24 / 2400 / FIDO 

CanogaPark / 818-992-4279 / 24 / 2400 

PlainRap / 818-772-8890 / 24 / 2400 

Night Gallery / 818-448-8529 / 24 / 2400 / StG 

QuantumLeap / 818-781-6573 / llp-8a / 2400 / StG 

Tesseract4-DCoCo / 818-340-4995 / 24 / 2400 / StG 

Zog'sCavem / 818-761-4135 / 8p-8a / 9600 / StG 

Discus / 819-771-3792 / 24 / 2400 / FIDO 

Color Nova / 902-634-3095 / 24 / 2400 

Nobody's Home / 904-245-6585 / 24 / 2400 / StG 

Kansas Konnektion / 913-738-5613 /24 / 1200 

The Dutchess CoCo / 914-838-1261 / 24 / 2400 / AcBBS 

09 Online/ 916-742-6809/24/ 1200 

Namia / 916-749-1107 / llp-8a / 2400 / StG 

Play House / 916-646-1907/24/ 2400 / FIDO 

Bill'sBoard / 919-395-4366 / 24 / 2400 


One will note that several networks are listed with the local 
boards. A network is a set of bulletin boards that share files 
with each other, usually just message files. One system 
operator calls another and transfers all the new messages and 
electronic mail to the other's system. This continues through 
out the network, one operator calling another in a predeter- 
mined order (usually worked out so that a minimum of long 
distance calls has to be placed) until the circle is completed- 
it then starts over again. In this fashion, a message placed on 
a local board may actually be answered by someone clear 
across the country in a matter of days or weeks, depending 
on the system. 

FIDO is the largest, most complex network in existence. It 
is also the oldest, having its beginnings in the dawn of the 
computer age. FIDO networks usually carry "echoes". An 
echo is a SIG or topic that has messages grouped in it. The 
message packets are transmitted from one board to another, 
either in a certain region or across the country. The mes- 
sages are thus "echoed" from board to board. The sysop of a 
particular BBS besides which echoes he/she wants to carry. 
They then find someone, preferably in their local calling 
area, to echo the messages to them. The calls are usually 
laced across the country to reduce long distance bills. 
Contact the sysop of a FIDO carrying board for more details. 

page 60 

Tandy's Little Wonder 

The Internet is a nationwide computer network established, 
or perhaps a better term is "cultivated", by the National 
Science Foundation (NSF). It is actually a collection of 
many regional networks all interconnected using a common 
communication protocol called the Internet Protocol or 
"IP". The raiginal intent was to enhance research and educa- 
tion projects through open communication and exchange of 
data. Development of the telecommunications backbone 
was subsidized by the govemmenL Up until very recently use 
of the Internet has been restricted to people or organizations 
involved in research and education. The guidelines govern- 
ing acceptable use have recently been relaxed to allow 
commercial companies and online services like De'phi to 
use Internet mail for many purposes. CompuServe, America 
Online, AppleLink, AT&T mail, MCI Mail, and now Delphi 
all have connections to the IntemeL 

There are literally thousands of services available through 
the IntemeL A feature called "FTP" allows users to transfer 
files from other hosts on the internet, and a feature called 
"Telnet" allows users to connect from one host to the other. 
FTP is short for File Transfer Protocol. With ftp you can log 
onto remote computer systems, explore their directories, 
and get files from them. Many remote sites permit anony- 
mous ftp, that is, you do not have to have an account with 
them to get the files from them. When you are asked for a 
usemame, you answer Anonymous. Then, if you are asked 
for a password, the traditional answer is to give your usemame 
and address, fw example, Other 
places allow you to logon to them only if you have an 
established account there. 

Before you can use ftp, you must know what address to use. 
You may find an address by searching fw a particular file 
with the ARCHIE utility, fat example , or get information 
from the various guides or from files in the database. Some 
good sources are: "The Whole INTERNET User's Guide & 
Catalog" - by Ed Krol, "The Internet Companion" - by Tracy 
LaQuey, "The Yannoff List" - A text file in the Delphi 
Database, "HYTELNET" - A Hypertext program in the Del- 
phi database (Mac and PC versions are on Delphi, and 
versions are available for other computers through ftp). 

Internet mail addresses are a combination of the name the 
person uses on the service, followed by an "(2)" symbol and 
then the Internet domain name used to identify the service 
itself. For example, the Internet address for Delphi member 
services is All Internet domain names 
(hosts) consist of two parts: the first part is usually the name 
of the organization (or an abbreviation) and the suffix is the 
type or organization it is. Businesses use the suffix "com", 
educational institutions use "edu". military sites use "mil", 
and government offices use "gov". Therefore, a person's 
address at CompuServe might be " 1 2345.678<a)compuserve. 
com" and a person at Harvard University might be "John 

A listserv is a discussion group where people exchange 
messages on a topic of common interest There are many 
hundreds of different listservs. You can subscribe to a 
listserv by sending Internet email to the listserv at its 
Internet address with the text SUBSCRIBE 
Name_of_Listserv YourFirstName YourLastName. When 
you subscribe, you will receive return mail acknowledging 
your subscription and in most cases telling you exactly how 
to sign off the listserv if you don't want to receive it any 
more. Some of the listservs produce hundreds of messages 
a week, so be careful! 

One must subscribe to Delphi's Internet services (S3/month) 
to use FTP and receive listservs. Mail may be sent to and 
received from individuals via Internet through normal Del- 
phi E-mail at any time. Simply use the persons' Internet 
address preceded by IN% and enclosed in quotes 
(IN%""). The extra charge is for the 
added communications time and storage space required by 
FTP and listserv support 

Other networks, such as StG Net, AcBBS. and RCIS were 
established by the BBS software writers. These networks are 
smaller and further apart than the large nets. They work 
essentially as FIDO does, one sysop calls another and passes 
the messages along the net. Due to the distance between 
locations, more long distance calls are necessary, but the 
time to transmit the smaller packets is shorter also. Though 
these nets are small, they deal strictly with CoCo and OS-9/ 
OSK topics. Contact the sysop of a BBS carrying one of the 
nets for more information. 




con OF 70 [ViHiNC NOUtS 

On DEI Ptll s 20/20 Advcnlage Plan, you get 20 tvyjii o( conoect time each month loi 
only S20 Additional lime o only 2 cents/minute No othei full teolufed online service 

even con->ei closel 

And triose ore 20 hours of real online tun and pfodJClivity Dowrtood (lies, chat with 
Iftends, send etectfonic moil, play mulli player games, ond moke Ifovel leservations 

With you/ CoCo and 

. Dial 1 -BOO- 365-4636 

. At Uiername type JOINDllMI 

. At Paawora type COCO30 



eaob44 acxA • 

Akeody Q DELPHI memDer? lype GO USING ADVANtAGE 

Tandy's Little Wonder 

page 61 

Current Publications 

There are still some publications currrently available that 
support the CoCo. Subscription prices are for one year (12 
issues) unless otherwise stated. Don't forget to look in the 
"National Clubs" section- those newsletters are nearly maga- 
zines in their own right and well worth the membership fees! 
Some local user groups also publish newsletters. 

the world of 68' micros was bom on the eve of "The 
Rainbows'" cessation of publication. Unlike the below listed 
publications, it will be a full size magazine with feature 
articles. Writers will include the likes of Marty Goodman, 
who will be writing a "hardware hacking" column. The first 
issue will appear in August of 1993. The magazine will be 
published every six weeks. Write for advertising informa- 
tion. Classified ads are accepted from subscribers, who 
receive 120 words per year free. Soft and hardware may be 
sold and traded in the classifieds (pirating not tolerated). 

ADDRESS: 904 2nd Avenue, Warner Robins, GA 3 1098 
PHONE: 912-328-7859 (info only) 
PRICE: Subscription - $23.00 U.S., $30.00 (U.S.) Canada & 
Mexico, $38 Foreign (air mail) 

NOTE: Special four issue trial subscriptions available (nor- 
mal rate divided by 2 + $1). Credit cards NOT accepted. 

UpTime is an eight page advertising newsletter with some 

editorial content. The main purpose is to provide a low cost 

advertising medium for vendors. Very good source for 

finding soft and hardware. Classified ads also available. 

PUBLISHER: JWT Enterprises 

ADDRESS:5755 Lockwood Blvd., Youngstown, OH 445 12 

PHONE: 216-758-7694 (info only) 

PRICE: Subscription - $15.00 U.S., $18.00 (US) Canada & 

Mexico, $22.00 (US) Foreign 

NOTE: Payment may be made in two monthly installments, 

first payment due with order. Credit cards NOT accepted. 

CoCo Friends is a disk based magazine. Requires a CoCo 

3. Supports DECB only. Graphics and programs included on 

disk. Fully automated to display cover and text articles... 

read on screen or print! Includes an editor for typing in 


PUBLISHER: Rick's Computer Enterprise 

ADDRESS: P.O. Box 276, Liberty, KY 42539 

PRICE: Subscription - $30.00 U.S., APO/FPO (six issues/ 

year). Single Issue - $6.00 

NOTE: No credit cards. Inquire about foreign rates. 

Nine-Times is another disk based magazine, except that it 
supports only OS-9. Runs in a supplied graphic enviroment, 
move around with mouse or joystick. Programs, help col- 
umn, hints & tips, C programming, Basic-09 programming, 
many more varied articles. Bound manual sent to new sub- 
scribers to ease installation and set-up of magazine shell. 
Requires OS-9 Level II (CoCo 3). 
PUBLISHER: JWT Enterprises 

ADDRESS: 5755 Lockwood Blvd., Youngstown, OH 445 12 
PHONE: 216-758-7694 (info only) 
PRICE: Subscription - $34.95 U.S., $35.95 (US) Canada, 
$42.95 (US) Foreign 

NOTE: Back issues available from May 1989. $7.00 each 
U.S., APO/FPO; $9.00 each all others. Credit cards NOT 

A Tribute to "The Rainbow", 1981-1993 

It is possible that The Rainbow is responsible for the CoCo 
being as much a success as it was. When Tandy wouldn't tell 
us what we wanted to know. Rainbow did. At one time, the 
Rainbow published over 200 pages per issue ! It was far from 
that when it finally ceased publication, down to 16 pages in 
a tabloid format. Yet, it was still packed with good CoCo 
information. It will be sorely missed by all CoCo users. 

The Rainbow started life on a CoCo and Tandy Line Printer 
VII (dot matrix, without lowercase descenders, even!), typed 
in with a little three line editor written by Lonnie Falk just 
for that purpose. The premier issue consisted of four pages 
copied at the comer dmg store... the four pages included the 
cover! Who would have thought that little newsletter would 
have grown into Falsoft, which is nw a publishing firm of 
some size? (note: the premier issue is still available!) 

Unfortunatly, the size of Falsoft (along with the dwindling 
number of CoCo users, and hence subscribers) is why The 
Rainbow ceased publication with the May, 1993, issue. 
Subscriptions had fallen to under 4,000 by that time. For a 
company of Falsofts' size, it was difficult to justify allocat- 
ing resources and personnel to continue publication... re- 
sources that could be put to more profitable use. It was not 
an easy decision for Lonnie Falk to let the Rainbow go. It 
must have been like losing a dear friend. We all feel that way 
Lonnie, but at least some of us understand the economics of 
the situation, and I hope others do after reading this. 


ADDRESS: P.O. Box 385, Prospect, KY 40059 
PHONE: 800-847-0309 (orders), 502-228-4492 (info) 
NOTE: Credit cards accepted. Sponsors CoCo and OS-9 
SIGs on Delphi. Programs also available for download 
($3.00 each charge). Back issues are $3.95 + $3.50 S&H for 
first issue, + $0.50 each additional (UPS), $5.00 for first + 
$1.00 each additional by U.S. Mail (U.S., APO/FPO only, 
foreign should inquire). Article reprints are $1.50 + $0.50 
S&H each article (only for out of stock issues). "Rainbow on 
Tape/Disk" back issues are $10 tape, $12 disk. 

page 62 

Tandy's Little Wonder 

The Color Computer Library 

The first section contains a list of books which will help you 
aquire a better understanding of the TRS-80 Color Com- 
puter, programming it, and its various systems. The word 
"COCO" (all capitol letters) is used to replace the words 
"Color Computer" in some titles. If the title uses "CoCo", it 
will appear in that form. The name and address of the current 
source will be listed if the book is still available. For the 
others, watch yard sales, flea markets, used book stores, 
classified ads on bulletin board systems (Delphi, 
CompuServe, GEnie, and local CoCo boards), and club 

The past magazine section lists all defunct magazines and the 
approximate dates of publication. Many useful programs and 
much information can still be found in these publications. 
Again, about the only place these will be found is through 
yard sales, classifieds, etc. In some cases, the publishers 
may be able to provide an index and photo copies of specific 
articles. Only those who MIGHT have photo copies available 
will have an address listed, so please inquire with a self 
addressed stamped envelope to ensure a reply. The excep- 
tion to this is The Rainbow. See previous page for back issue 
ordering information and prices. 


1978 MC6809 Macro-Assembler Ref. Manual Motorola 

1979 MC6809 Preliminary Programming Manual 

1980 The MC6809 Cookbook Carl D. Warren 

1981 MC6809-MC6809E Microprocessor Program- 
ming Manual Motorola 

1980 The MC6809 Cookbook Dr. Carl Warren 

1981 101 COCO Programming Tips & Tricks Ron Clark 
1981 55 COCO Programs For Home & School & Office 

Ron Clark 
1981 55 MORE COCO Programs For Home School & 

Office Ron Clark 
1981 6809 Assembly Language Programming 

Lance Leventhal 
1981 6809 Microcomputer Prog & Interfacing 

Andrew Staugaard Jr. 

1981 The Facts Spectral Associates 

1982 COCO Graphics (RS) William Harden, Jr 
1982 TRS-80 COCO Programs (RS) 

Tom Rugg & Phil Feldman 
1982 TRS-80 COCO Quick Reference Guide Radio Shack 
1982 The Color Computer Songbook Ron Clark 
1982 Color Computer Graphics Ron Clark 
1982 TRS-80 COCO Graphics Don Inman with Dymax 
1982 Programming The 6809 

Rodnay Zaks & William Labiak 
Motorola (see "The Motorola Connection") 
FARNA Systems, 904 2nd Ave., Warner Robins, GA 3 1098 

1982 COCO Secrets Revealed Disk 'N Data 

1983 TRS-80 COCO Interfacing With Experiments 
Andrew Staugaard Jr. 

1983 TRS-80 Color Basic Bob Albrecht & John Wiley 
1983 Troubleshooting & Repairing Personal 

Computers Art Margolis (2nd edition, 1993, also) 
1983 TRS-80 Mod I, III & COCO Interface Projects 

William Harden Jr. 
1983 TRS-80 Extended Color Basic Richard Haskell 
1983 Top-Down Basic For The COCO Ken Skier 
1983 Assembly Language Graphics For The COCO 

Don Inman 

1983 How To Do It On The TRS-80 William Harden Jr. 

1984 500 POKES, PEEKs 'N EXECs Kishore M. Santwani 
Zebra Systems, 131 Joralemon St.#52, Brooklyn, NY 1 1201 

* All three Pokes/Peeks/Exec books available. 
1984 Color Basic Unraveled Spectral Associates 
1984 Extended Basic Unraveled Spectral Associates 
1984 Disk Basic Unraveled Spectral Associates 
1984 Things To Do With Your COCO 

Willis, Miller, & Johnson 
1984 COCO Assembly Language Programming (RS) 

William Harden Jr. 
1984 COCOINDEX Dean Norris 

1984 Your Color Computer Doug Mosher 

1985 Complete Rainbow Guide To OS-9 
Dale Puckett & Peter Dibble 

Rainbow Book Shelf, P.O. Box 385, Prospect, KY 40059 

1985 Utility Routines for the Tandy & COCO, Vol. I 
Kishore M. Santwani 

1986 THE BOOK: Assembly Language Programming 
for the TRS-80 COCO Tepco 

Tepco, 30 Water St., Portsmouth, RI 02871 
1986 Utility Routines For the Tandy & COCO, Vol. II 
Kishore M. Santwani 

1986 Supplement To 500 POKEs, PEEKs & EXECs 
Kishore M. Santwani; Zebra Systems (see 1984) 

1987 THE ADDENDUM (CoCo 3 supplement to THE 
BOOK) Tepco (see 1986) 

1987 Super Extended Basic Unravelled 

Kishore M. Santwani 
1987 300 POKES, PEEKS N' EXECS for the CoCo III 

Kishore M. Santwani; Zebra Systems (see 1984) 

1987 The Complete Rainbow Guide to OS-9 Level II, 
Vol. I: A Beginners Guide to Windows 

Dale Pucket & Peter Dibble; Rainbow Bookshelf (see 1985) 

1988 Start OS-9 (step by step tutorial) Paul K. Ward 

1989 A Full Turn of the Screw ('83-'89 Articles from 
Rainbow) Tony DiStefano ;Rainbow Bookshelf (see 1985) 

1990 Connecting CoCo to the Real World 
William Barden Jr. 

1992 The OS-9 Catalog (description of all OS-9/68000 

modules, useful for OS-9/6809 also) 

Microware, 1866 N.W. 1 14th Street, Des Moines, lA 50322 

Tandy's Little Wonder 

page 63 

Past Magazines 

The Color Computer definitely had its' share of publications 
over the years! The large ones were Hot CoCo, The Color 
Computer Magazine, and The Rainbow. These were all 
three published simultaneously during the CoCos' heyday. It 
wasn't long before all succumbed except for "The Rainbow". 
According to Lonnie Falk, founder of "The Rainbow" and 
Falsoft, the others just didn't offer as much as "The Rain- 
bow". That may very well be true, as it is doubtful that "Hot 
CoCo" and "The Color Computer Magazine" combined had 
as many subscribers during the CoCos' "golden years" as did 
"The Rainbow". Even so, back issues of all are still valuable 
information sources... they were for this book! 

TRS-80 Microcomputer News (all Tandy computers) 

September '80-July '84 Tandy 

80 Microcomputing (80 Micro, all TRS-80 computer) 
October '80-May '83 March '86-.... CW Communications, 
80 Pine Street, Peterborough, NH 03458 
68 Micro Journal 

November '80-July '83, March '85-1990 ... Don Williams 
BYTE Magazine (various articles, not in every issue) 
October '80-'83 
The Color Computer News 

June '81-September '83 REMarkable Software 

Chromasette (cassette mag through July '83, disk after) 

July '81-July '84 Chromasette 

The Programmer's Institute TRC (cassette/disk mag) 

November '81-March '84 (?) Future House 

The Color Computer Magazine 
March '83-October '84 Ziff-Davis Publishing, 

One Park Avenue, New York, NY 10016 
HOT CoCo! 

June '83- February '86 CW Communications, 

80 Pine Street, Peterborough, NH 03458 
Dragon User (specifically for Tano Dragon) 
August '83-September '86 ... Business Press International, 

205 E. 42nd Street, New York, NY 10017 
68 Color Micro Journal 

September '83-February '85 Don Williams 

Dynamic Color News 
February '84-January '89 (?) .... Dynamic Electronics, 

Box 896, Hartselle, AL 35640 

December '84- June '85 Green Mountain Micro 

DIGInews (cassette magazine) 

April '85-April '86 (?) Dragonfly Writing 

CoCo Time (disk magazine) 

October '85-July '86 Microcom Software 


November '86- June '87 Spectrogram Magazine 

TRS-80 Computing/Color Computing (bi-monthly) 
June '87-October '91 Color Computing, 

65 Oak Road, Canton, MA 02021 

The 68xxx Machines (OSK/OS-9) 

Feb '91-July '92 The Chatham House Company 

c/o Jim DeStafeno, RD#1 Box 375, Wyoming, DE 19934 

The Motorola Connection 

Since Motorola is the manufacturer of the 6800/68000 
series of microprocessors, it is natural that they should have 
several useful publications available. The current emphasis 
is on the newer 68000 series, but books containing informa- 
tion on the CoCos' 6809 are still available. Write to Mo- 
torola and ask for the "Technical Literature and Information 
Guide", #BR10 1/D. If one is interested in building or devel- 
oping projects using Motorola products, also ask for "Appli- 
cations Literature", BR135/D, which is a listing of technical 
articles and engineering notes describing specific applica- 
tions. Many of the articles and notes contain complete 
schematics. Data pamphlets for the various Motorola chips 
used in the CoCo are available for the asking 

Motorola Literature Distribution Center 
P.O. Box 20912, Phoenix, AZ 85036-0924 

Motorola Ltd. European Literature Center 

88 Tanner's Drive, Blakelands Milton Keynes, 


Nippon Motorola Ltd. 

4-32-1, Nishi-Gotanda, Shinagawa-ku 

Tokyo 141, JAPAN 

Motorola Semiconductors H.K. Ltd. 

Silicon Harbor Center, No. 2 Dai King Street 

Tai Po Industrial Estate 

Tai Po, N.T., Hong Kong 

Foreign Sales Offices and Phone Numbers: 
Austraha- Melborne: (61-3)887-0711 
Sydney: (61-2)906-3855 
Germany- Munich: 49 89 92103-0 

Wiesbaden: 49 611 761921 
The Netherlands- Best: (31) 4998 612 11 
Switzerland- Geneva: 41(22)799 1111 

page 64 

Tandy's Little Wonder 

Technical Reference Section 

...covers all the hardware aspects of the CoCol 



A peripheral is any hardware item attached to the computer. 
These include Video Display Devices, Mass Storage Sys- 
tems, Printers, Expansion Devices, and many more special- 
ized attachments. The primary CoCo peripherals will be 
discussed individually, with other, less common items 
grouped together. 

1. Video Display Devices 

One of the most important peripherals for any computer is 
a video display device. In the early days of personal comput- 
ing, when a 4K, non-extended basic CoCo 1 sold for $399, 
most personal computers (even the original IBM PC) relied 
on a standard television set for a display. No wonder... even 
the relatively low resolution TRS-80 Model 1 monitor sold 
for $199, and it was only capable of adequately displaying 16 
lines of 64 characters in black and white. Note that this and 
other monitors of the day were really nothing more than TVs 
modified for direct video input and increased bandwidth. 
This was comparable to most other monochrome (green 
screen) monitors which were inferior in many ways (B&W 
resolves graphics with more shades than monochrome., how 
many shades of green or amber are easily separated by 
sight?). Composite color monitors were selling for as much 
as $349, and were no more capable than lower cost B&W 
models (all prices circa 1982). The CoCo was designed as a 
low cost color capable computer, and most people already 
had color TVs, so the TV was the only officially supported 
display device until the 1986 release of the CoCo 3, which 
supported TV, composite video, and RGB Analog video. 
Support for these devices was long overdue, as prices had 
come down to under $100 for monochrome composite 
monitors and to around $300 for RGB monitors. 

The following paragraphs explain in detail the various as- 
pects of each of the main types of video displays available to 
CoCo owners. There are certain advantages and disadvan- 
tages for each. Choose carefully and use whatever fits your 
needs and budget. 

The first video device most people consider for the Color 
Computer is a standard television set. This is usually 
adequate for games, the low resolution text screens (32 and 
40 columns), and the CoCo 3 medium resolution screen (64 
columns). Some CoCo 1/2 software generates a 51 and/or a 
64 column screen, which also resolve adequately on a TV. 

When choosing a TV set, stick with a 10 to 16 inch screen. 
A color TV only has a maximum usable resolution of 
256x256, which means 256 dots left to right, 256 lines from 
top to bottom. This means that there are a total of 65,536 

dots on the entire screen. The smaller the screen, the closer 
those dots are and the better the picture will appear to be. 

A black and white TV will give a superior text display. 
There is less signal data to decode in a B&W signal. Color 
will look better with games, the difference between color 
and B & W will basically be the same as watching color versus 
B&W TV shows. Text displayed on a color set will have a 
"fuzzy" colored edge around the letters, caused by the color 
burst signal. This can be reduced by turning the color all the 
way out on sets with a color adjustment or by turning the 
color burst signal off via software on a CoCo 3. Turning off 
the color burst requires machine language programming for 
the CoCo 1/2. CoCo 1/2 programs using high density text 
screens usually have this feature built in. Changing colors 
also helps. A problem is that most programs will override 
your changes. Some text based software automatically turns 
the color burst off A 10-12 inch B&W TV will render 
readable, though small, 80 column text in most cases with no 
hardware modifications. 


40/80 column text on TV or Composite monitors: 

10 WIDTH 80 : REM or 40 

20 POKE &HE033,16 : POKE &HE03C,19 : POKE 

&HE045,19 : REM turn off color burst 

30 PALETTE 8,255 : REM change background color 

40 PALETTE 0,0 : REM change foreground (character) 


Try experimenting with the PALETTE values. 8,63 andO,Oor 
0,63 and 8,0 may be more to one's liking. 

The TV signal coming out of the CoCo is not the best. Though 
the cable supplied by Tandy is shielded, it is small and 
interference will be noticed- especially with disk drives. The 
best way to remedy this would be to get a composite or RGB 
monitor and avoid use of a TV altogether. Fortunately, there 
is an easier solution! What is needed is better shielding on 
the cable between the TV and computer. Simply get a suitable 
length of 75 ohm cable (the type used with cable TV, VCRs, 
and antennas) with "F" connectors on each end (RS #15- 
1536 is a 6' cable). Plug one end into a cable ready TV or 
cable TV adapter (RS #15-1140, or 6' cable with adapter 
built-in for use with antenna leads OR cable ready TV, RS 
#15-1522), and plug the other end into the CoCo. An "F" 
connector to phono plug adapter will be required to connect 
the 75 ohm cable to the phono plug on the back of the CoCo 
(RS #278-252). All this will resuft in about a 100% im- 
provement in video quality at a cost of under $10... well 
worth the investment! 

Tandy's Little Wonder 

page 65 

The next video type to consider is composite video. This is 
basically a TV without a tuner, but is much clearer . Compos- 
ite monitors are readily available as combination color TV/ 
monitors, usually for use with high quality VCRs. Harder to 
find nowadays are monochrome (single color, usually green 
or amber) composite monitors, which are really needed 
for 80 column text display, for the same reason that B&W 
TV is superior to color. As good as monochrome are B&W 
composite monitors. These are usually available at security 
dealers as they are frequently used for surveillance systems. 
Check with surplus electronics dealers for composite moni- 
tors of all types (Timeline Inc., 1490 W. Artesia Blvd, 
Gardena, CA 90247, 213-217-8912, for example). 

If TV and composite are virtually the same, then how is 
composite better? Composite video monitors reduce the 
sources of possible interference and allow an increase in 
bandwidth. TV tuners and RF modulators (the metal box 
inside the CoCo that converts the video signal to a TV signal) 
are great sources of interference. The modulator is actually 
a low power TV transmitter that broadcasts via direct wiring 
over the channels selected by the switch on the back of the 
computer (3 or 4 on U.S. model CoCos). These modulators 
must comply with strict regulations set by the communica- 
tions authority in the country of use (FCC in the U.S.), and 
bandwidth (signal width) is limited to a maximum of 3 . 5MHz 
for B&W sets, 3.0MHz for color. A composite monitor 
overcomes all this by eliminating the interference sources 
(modulator and tuner) and extending the bandwidth (though 
only to 3.5MHZ for composite color models). Due to a 
wider bandwidth, monochrome and B&W monitors are 
capable of a maximum resolution of 648x264 (dots x lines). 

To use a composite monitor, simply plug a video patch cable 
between the video and audio jacks on a CoCo 3 to those on 
a monitor or TV/monitor. A CoCo 1/2 will require a video 
amplifier to add direct video output. At one time these were 
readily available, but are not in much demand anymore 
(Dynamic Electronics may still have some). Anyone some- 
what handy with a soldering iron can build the simple circuit 
shown. This will allow plugging into a color or mono com- 
posite monitor. If the monitor in question doesn't have 
sound, a stereo or simple audio amplifier can be used (RS 
#32-2031 or #277-1008). Get sound output by soldering 
the center lead of a female RCA phono jack to pin 3 (marked 
on mother board) of the RF converter (the silver box the TV 
plugs into) and the outer lead to ground. Almost any audio 
amp IC can be used to build a simple circuit to drive a small 
speaker, which could be mounted inside the CoCo case. 

Tandy produced a number of CoCo 1/2 models with com- 
posite video but no RF or audio circuitry. These were for use 
in classroom network systems originally sold only to 
schools. Some of these have become available as schools 
upgrade their classroom computer systems. Note that the 
turning off the colorburst signal and changing colors on a 
CoCo 3 will produce better text, just as with a TV set. 

A TV without composite input can have the input added. 
ously higli levels of current in a TV, ESPECIALLY 
COLOR SETS! DO NOT attempt this on old tube type sets 
or sets known to have a "hot chassis". These sets have one 
side of the AC power cord connected directly to the metal 
frame inside the TV (the chassis), and present a SEVERE 
MODERN COLOR SETS! Therefore, this modification is 
only recommended for B&W sets (other reasons are ex- 
plained in the following text). Always use a solid state or 
transistor TV that has a power transformer. Most B&W TVs 
made over the last 10 years or so should be safe, but do look 
before continuing. Any AC/DC portable set will work well 
warnings given, I'll continue... 

Adding the video input directly is incredibly simple. All that 
is required is five components, a small piece of PC board, 
and a bit of wire. Use a female RCA type phono jack for the 
input, either mounted to the TV cabinet or a short piece of 
cable (#274-346 or #274-338). The shield (negative) side is 
grounded to the chassis (hence the shock hazard for "hot 
chassis" sets!). The positive (center) lead is connected to the 
chassis through a 470 ohm resistor, and to the base of the 
video driver, right before the bias circuit, through two 
1N914 or 1N4148 diodes and a single 0.1 uF capacitor. The 
hard part is finding the video driver transistor in the TV. 
There is usually a schematic inside the case of most TVs. 
Use this to locate the video driver transistor. If no sche- 
matic, one must be located or the project referred to a 
qualified TV technician. TV technicians should be able to get 
a schematic for a reasonable fee. A speaker circuit will have 
to be used, as the sound from the TV signal is no longer 
available. If the TV is to be used solely as a computer 
monitor, wire the circuit in directly. Otherwise, add a switch 
between the video input circuit and video driver. 

With a color set, this is the limit to the modifications that 
will improve the display as there is an essential 3.58MHz 
colorburst signal. It is therefore best to use a B&W TV, as 
the signal can be further improved... enough to adequately 
display 80 column text. The easiest additional modification 
for a B&W TV is elimination of the 4.5MHz sound trap. This 
is done either by cutting the circuit board trace connecting 
a series wired trap or adding a jumper around a parallel wired 
trap. A switch will have to be used to cut the trap out or bypass 
it if the set is to be used for normal TV reception. Eliminat- 
ing the sound trap widens the bandwidth to 4. 5MHz, enabling 
80 column displays to be viewed without undue eye strain. 
The above are the extent of practical TV modifications for 
the average hobbyist to accomplish. For further informa- 
tion, consult TV Typewriter Cookbook by Don Lancaster, 
chapter 8 (last known printing 1981, Howard W. Sams & 

page 66 

Tandy's Little Wonder 

Typical Black and White (B&W) TV Circuit 

+12V I ^g\f^ 

I ^ I^JND Brightness 

Sync Adjustment 

j Sound ^^\ sN\N 

Last Video IF 


Direct Video Input 

Sound Trap Eliminations 

Combined trap/pick-off circuits handled the same as similar traps. 
I Add Jumper Here | 




Parallel Resonant Trap 

Video _y^ 

Cut Trace 


Series Resonant Trap 

Tandy's Little Wonder 

page 67 

Co., 4300 West 62nd Street, Indianapolis, IN 46268), avail- 
able in many public libraries, the publisher, or directly from 
the author (Synergetics, Box 809, Thatcher, AZ 85552, 
phone 602-428-4073). 

By far the best video source is an RGB color monitor. 
"RGB" means that the signals for three colors- Red, Green, 
and Blue - are sent from the computer to the monitor 
separately, where they are then combined in varying degrees 
to form colors. Only the CoCo 3 is made to deliver RGB 
output. There is no simple way to add RGB output to a CoCo 
1 or 2. Since an RGB monitor receives the video signal 
directly, and no mixing/separating circuitry is required, 
there are no bandwidth limitations other than those imposed 
by the monitor design itself This allows an increase in 
resolution, again limited only by the monitor design and 
signal delivered to the monitor. The CoCo 3 will deliver a 
maximum resolution of 640x192, and 640x225 is possible 
with special machine language programming. The monitors 
used with the CoCo 3 will support a maximum resolution of 
640x200, the limiting factor being the bandwidth 
(15.75KHZ... compare THAT to a TV's 3-3.5KHz signal!) 
and dot pitch (width). In general, the smaller the dot pitch, the 
sharper the image (a CM-8 had a dot pitch of .52mm, the 
popular Magna vox 8CM515 and 1CM135 is only .42mm). It 
is not advisable to get a monitor with a dot pitch of more than 
.52mm for viewing 80 column text. An RGB monitor will 
support all screen modes from 32 to 80 columns. 

Note that RGB monitors do not support "artifacting"- a 
programming technique used by some CoCo 1 and 2 pro- 
grams to generate additional colors on screen. Programs 
using artifacted colors will display as black and white on an 
RGB monitor. There is no easy way to fix this problem. 
When the CoCo 3 first appeared, a few vendors sold patch 
programs to display artifacted programs in color on an RGB 
monitor. Unfortunately, most of these programs are no 
longer available. There are a few patches available from the 
Delphi CoCo SIG for specific programs. Perhaps the best 
solution is to purchase a monitor that displays both RGB and 
composite video (such as the 1CM135 and 1084, and almost 
all TV/monitor combinations). 

There are two basic types of RGB monitor that will work 
with the CoCo 3. The first is an ANALOG type. An analog 
signal varies almost infinitely from 0-.9V, allowing a large 
range of colors (limited to 64 colors by the CoCo 3). This 
is the type the computer is really designed to use, ala the 
Tandy CM-8 . The most widely available monitors that accept 
this type signal are the Commodore 1084 (for the Amiga) 
and Magnavox 1CM135 (note that the Commodore 1084 is 
made by Magnavox for Commodore... it is almost identical 
to a 1CM135). The Commodore 1084S also works- it is just 
a 1084 with two speakers for stereo sound (hence the "S"). 
All three sold for just under $300 new at the time of 
publication. An analog monitor was used because of the high 
number of colors for minimal hardware cost. 

Some other monitors that will work are listed below (note 
that many are no longer being manufactured). Monitors 
followed by an asterics (*) have both RGB and composite 
inputs. Both may be connected to the CoCo 3 at the same 
time, which allows switching between RGB and composite 
for games that use artifacted colors (a color TV may also be 
connected in conjunction with an RGB monitor. . . indeed, the 
CoCo 3 will drive all three video devices at once!). The dot 
pitch is listed in parentheses when known: 
Commodore 1902 

Commodore 1084 and 1084S (.42mm)* 
Magnavox 8CM505 (.65mm) 
Magnavox 8CM515 and 1CM135 (.42mm)* 
Magnavox 8CM643 (.39mm) 
NEC Multisync (.31mm) 
Teknika MJ305 (.41mm) 

Other RGB Analog monitors are also usable. The CoCo 3 
uses separate (horizontal and vertical) "up-going" (posi- 
tive) sync signals. The below listed monitors differ from 
these standards but are usable with a little added circuitry. 


SYNC: Feed both the H and V sync signals from the CoCo 

3 into the inputs of a NOR gate (74LS02) and feed the output 

to the monitor's combined input. The NOR gate can be 

piggybacked on top of IC 15 (74LS04) in the CoCo 3 where 

the H and V signals and +5V and ground for the chip are 

readily available. Monitors followed by an asterics (*) have 

both RGB and composite inputs. The dot pitch is listed in 

parentheses when known: 

Commodore 1080 * 

SONY KX-1211HG (.39mm) 

SONY CDP-1201 (.25mm 

SONY CDP-1302 (.25mm) 

SONY CDP-1310 (.37mm) * 

SONY KV-1311CR TV/monitor (.37mm) 

SONY CDP-9000 (.25mm) * 

SONY KV-20XBR (.37mm) * 

SONY KV-2011CR (.37mm) * 

SONY KV25XBR (.55mm) * 

SONY KV-2511CR (.55mm) 

NOTE: The Sony "K" series are TV/monitor combinations. 

The first two numbers indicate picture size except for the 9" 


Atari ST RGB color monitors are also usable. They 
require separate negative sync signals. One would have to 
run the CoCo 3 s' positive sync signals through inverter gates 
(74LS04) before connecting to the Atari monitor. 

The second type RGB monitor is the DIGITAL type. This is 
the type used by IBM for their first color monitor for use 
with their color graphics adapter, hence the common desig- 
nation "CGA". The sync signals are correct for the CoCo 3, 
so just connect all the lines from the CoCo 3 connector to 
their counterparts on the CGA monitor connector. Digital 

page 68 

Tandy's Little Wonder 

signals are either on (+5V) or off (OV). Each of the three 
signals (RGB) can only be combined in such a way as to 
display six colors, and two of those colors are black and 
white (RGB all off or all on). Another pin on the CGA type 
monitor doesn't have a counterpart on the CoCo 3 . This is the 
"intensity" pin (which leads to the designation of RGBI for a 
digital monitor). By using this signal even an IBM type 
computer can display only 16 colors. The limited resolution 
(640x200) and color set led to the development of higher 
resolution analog monitors for IBM type computers. While 
these higher resolution monitors are not normally usable 
with the CoCo 3, it does mean that used CGA monitors are 
readily available at electronic and amateur radio (HAM) 
swap meets at reasonable prices... around $100 or less 
(around $200 new). While some game screens may be hard 
to read due to the limited color selections, 80 column text 
will be easily readable. 

COCO 3! These monitors sync at faster rates than the CoCo 
3 and damage to the monitor and/or computer WILL result. 
Only monitors known to be compatible with CGA or that are 
known to sync at 15.75KHz should be connected to a CoCo 
3. Note that many expensive Multi Sync monitors support 
15.75KHz, but not all. Check with the owners manual or 
manufacturer to find out. Even today, multi sync monitors 
are somewhat expensive. The only reason they are men- 
tioned here is that they can be used with higher resolution 
IBM type machines as well as a CoCo 3, so if one has both 
machines one monitor may suffice, though both computers 
obviously can't be used at the same time. 


1&2 Ground 


4 Green 12 3 4 5 

5 Blue 6 7 8 9 

6 not used 

7 Sound (pin usually missing) 

8 Horizontal Sync 

9 Vertical Sync 

It is possible that some monitors will shift the display one or 
two characters to the left. This is a hardware problem within 
the CoCo 3, not the monitor. Try cleaning the GIME and 
socket by carefully prying out the chip (remember how it is 
oriented in the socket!) and cleaning the chip with a pencil 
eraser, the socket with rubbing alcohol. If this doesn't cure 
the problem, replace capacitor C-64 (150 picofarads... the 
only "C-64" a CoCo user should ever be concerned with!) 
with a 220 picofarad capacitor of the same type. The prob- 
lem rests in timing, which is affected by capacitance. 

2. Mass Storage Systems 

Mass storage is considered anything that (more or less) 
permanently holds a program or data. Four major types of 
storage are available for the CoCo- ROM Pak, Tape Drives, 
Floppy Disk Drives, and Hard Disk Drives. Luckily, the 
CoCo was never subjected to punched tape! 

ROMs (Read Only Memories) are definitely mass storage, 
but onlyoneway.A ROM can be read and a program executed 
from it, but it can't store new information. Therefore, ROM 
Paks have to be used in conjunction with tape (or in some 
rare exceptions disk) if any information is to be stored. 

A program stored in a ROM for the CoCo is normally a 
machine language program. BASIC programs can be stored 
in a ROM, but must include a m/1 loader to move them into 
an area where BASIC can run them. The computer detects the 
presence of a ROM Pak through the CTS (cartridge select) 
signal on the expansion port or MPI. The CART (cartridge 
detect interrupt) line senses the presence of a ROM Pak 
also, and auto executes it. Auto execution can therefore be 
deterred in all but a very few ROM Paks by taping over pin 
eight on the cartridge itself The ROM can then be executed 
by typing EXEC 49152 (CoCo 1/2 ONLY) or EXEC 57360 
(CoCo 3 ONLY), or the information can be saved to tape 
with: CSAVEM (name),49152, 65279, 49152 This will save 
a standard 16K ROM Pak (all CoCo 1/2 Paks are only 16K) 
to tape. A special program or patch has to be used to save and 
run the larger ROM Paks from RAM. Patches for some are 
available from Delphi or FARNA Systems. 

The first mass storage system time CoCo users were intro- 
duced to was the cassette recorder. Tandy made several 
recorders with computers in mind (CTR and CCR series.. 
Computer Tape Recorder and Computer Cassette Recorder), 
but any portable cassette recorder with a remote, micro- 
phone, and earphone j ack will work (on the CTR/CCR series, 
the AUX jack is used instead of the earphone jack). The first 
problem with cassettes is that they are SLOW. It takes a few 
seconds to load or save even a short program. The second 
major drawback is that files cannot be randomly accessed- 
the entire file must be read into memory before use (in most 
cases), limiting the amount of data that can be worked with. 

When using tape, one must be careful to start loading only at 
the beginning of a file. An I/O error will occur if a load is 
attempted in the middle of a file. An easy way to locate a file 
is to type MOTOR ON : AUDIO ON. This turns the monitor 
speaker and tape motor on, allowing one to listen for the 
beginning of a file. Another method is to pull the remote and 
earphone jacks and listen through the recorder speaker. The 
Tandy recorders come in handy for either method, as they 
have a "cue" and "review" feature which allows rewind and 
fast-forward operations while still listening to the tape (the 
buttons must be held half depressed). 

Tandy's Little Wonder 

page 69 

Tape I/O for the CoCo normally occurs at 1500 bps. Tape 
operations can be sped up (to approximately 2700 bps) by 
using the double speed POKE (POKE 65495,0 for CoCo 1/ 
2, POKE 65497,0 for CoCo 3) to save. Load by typing 
POKE 143,14 : POKE 144,24 : POKE 145,6 CLOAD 
"name" (or CLOADM) while in double speed mode; POKE 
143,8 : POKE 144,24 : POKE 145,4 at normal speed. POKE 
143,18 : POKE 144,24 : POKE 145,10 restores to the 
normal rate (1500 bps). Only high quality tapes should be 
used, especially when using high speed mode. In general, the 
higher quality the tape, the fewer I/O errors one is likely to 
experience whether using double speed or not. 

Note that Radio Shack no longer lists computer cassettes 
(#26-302 10 minute, #26-308 20 minute). They do have 
leaderless five and ten minute answering machine cassettes 
(two and a half and five minutes per side, #43-437 and #43- 
4399) that are practically the same as the older computer 
cassettes. These shorter tapes are easier to work with. It 
is good practice to store only one file per tape with three or 
more copies of that file on the same side, one after another. 
If the program is used often, put multiple copies on both 
sides. This prevents having to rewind a lot- just make sure 
there is a bit of blank tape between copies. 

Floppy disk systems were rather expensive in the early days 
of home computers (the first Tandy system was $499). A 
cheaper alternative was therefore a modification of the basic 
tape drive- the Exatron Stringy Floppy (ESF) system. This 
system used an endless-loop tape cartridge called a "wafer". 
A typical wafer would store around 70K of data and up to 99 
files. The good points about the ESF was that random access 
files were possible, it plugged into the standard cassette 
cable, it was faster than cassette (7200 bps compared to 
1 200 bps for cassette. . a 1 6K program loaded in less than 20 
seconds... wait a couple MINUTES for cassette to load), and 
the cost was about 2/3 of a disk set-up (under $300 in 1982). 
The major drawback was that only Exatron made the thing, 
limiting availability of software (though Exatron DID line up 
some popular products). Another drawback was that the 
operating system had to be loaded from tape before use, and 
some m/1 programs would write over the operating system, 
making the system useless (note that the operating system 
resided in memory normally reserved from use, but clever 
m/1 programmers often re-mapped CoCo's memory to get a 
few more bytes of program space). The Exatron was pretty 
popular in the early days, enough that it was made for a 
number of computers and recognized by most knowledge- 
able computer hobbyist. It faded from the market around 
1983 as competition and demand drove disk drive system 
prices close to the cost of an ESF system. 

density, single sided, 35 track drive (80K capacity), drive 
case, and power supply. One reason Exatron dropped the disk 
drive in favor of the ESF was the amount of RFI (Radio 
Frequency Interference) generated by their disk system. 
Properly shielding circuit boards and cables drove up the 
cost of a good disk system... RFI problems were virtually 
non-existent with tape drives. The early Exatron disk system 
generated so much RFI that the TV screen was unreadable 
during disk access. Within months after delivering these 
systems, Exatron was taking them back! The FCC finally had 
to step in and lay ground rules for the amount of RFI a home 
computer could generate. Exatron finally got the RFI prob- 
lems straightened out late in 1982. 

Tandy released it's own disk system for the CoCo in 
October of 1982. The retail price for this system was $499, 
but the drives were single sided, 35 track, double density 

units capable of storing 176K. An Exatron system required 
two drives at about the same total cost to come close to this 
storage capacity. The Tandy drive quickly drove the Exatron 
system out of the market simply because software develop- 
ers naturally chose the Tandy for compatibility. Had the 
Exatron used double density drives, there may have been a 
way to make the systems compatible. The first Tandy con- 
troller (drive kit 26-3022) required 12V to operate. Later 
models were 5V only. The 12V controller can be used with 
a CoCo 2 or 3 only through an MPI, which supplies the 
necessary voltage. It is not reliable at double speed disk 
operation even if DECB has been modified for double speed 
(OS-9 Level II operates at double speed only). 

There were several other early disk systems made, but all 
failed to gain support as they were not fully compatible with 
the Tandy system. The operating system was usually the 
major problem. Tandy didn't develop a disk operating 
system (DOS) per se. What was developed was an exten- 
sion to the existing BASIC language that allowed direct 
disk operations. If one has ever programmed in GW- 
BASIC or BASIC -A on an IBM compatible, then the fact that 
many disk activities can't be done in BASIC is known. The 
DOS (PC-DOS or MS-DOS) must be called to perform all 
but the most rudimentary disk operations (such as a direc- 
tory). Tandy's Disk Extended Color BASIC (DECB) can 
write and read directly from disk, and is much more conve- 
nient to program disk operations with. The term "RS- 
DOS" is often used to refer to DECB, but the term is 
technically incorrect. Only two versions (1.0 and 1.1) of 
DECB were ever published by Tandy. The CoCo 3 changes 
the first one to a two (2.0/2.1) but does not alter the disk 
commands themselves. DECB must be patched for reliable 
double speed disk operation. 

With all the deficiencies of tape it is no wonder that the more 
expensive floppy drives eventually won out. Exatron was 
responsible for the first floppy disk systems for the CoCo. 
The Exatron system was advertised in July of 1981 for only 
$298 and included a controller with 16K RAM, a single 

CoCo drives are numbered from to 3, meaning four single 
sided drives can be accessed. Tandy chose an odd method of 
selecting which drive was which- by removing the contacts 
from the connector of the three that the drive wasn't! This 
method had one merit- it was foolproof All the drive select 

page 70 

Tandy's Little Wonder 

jumpers could be selected on a drive from the factory. 
Anyone could then plug in a drive and it would work prop- 
erly... no configuration necessary! Another oddity was that 
position 32 on the cable was used for drive select 3 instead 
of position 6, which was used by all other manufacturers. The 
problem with this was that position 32 is the side select line! 
Position 6 is unused on Tandy cables. To use four single 
sided drives position 32 must be jumpered back over to 
position 6. There is good reason NOT to do this- use of 
double sided drives (explained later). 

The first fully compatible aftermarket disk controller was 
manufactured by J&M Systems, introduced in April of 
1983. This controller was quite popular due to its compat- 
ibility with the Tandy system. The controller was shipped 
with JDOS, a J&M version of DECB, but a standard Tandy 
DECB ROM could be used as well. Later models had two 
external switch controlled ROM sockets and a parallel 
printer port (accessed through JDOS or modified DECB 
ROM). One of the ROM sockets supported a 24 pin ROM 
(such as the DECB ROM) and the other a 28 pin (such as 
popular, low cost Intel EPROMs required). A smaller con- 
troller was released in 1987 that contained no parallel port. 
J&M sold production rights of the small controller to Owl- 
Ware (who still produces it) late in 1988. A full drive kit 
from J&M was priced just $50 less than Tandy's, but used 
higher quality TEAC drives. 

Another controller worthy of mention was the Hard Drive 
Specialist floppy disk controller. This controller had two 
ROM sockets (one 24 and one 28 pin) also, but no external 
switch for selecting which one was active (this was done by 
a set of internal jumpers). The HDS controller could support 
two 24 pin ROMs by setting jumpers inside the controller. 
The second 24 pin ROM was then placed in the 28 pin socket. 
The DECB ROM supplied by HDS was usually enhanced for 
faster disk access times, as only the oldest Tandy drives 
required the DECB default of 30ms. HDS sold CoCo disk 
controllers from 1985-1989. 

About the most well known aftermarket supplier of CoCo 
hardware is Disto. They introduced a disk controller, the 
"Super Controller" as their first product in 1985. This 
controller had four 28 pin ROM sockets and came with C- 
DOS, which was DECB compatible. The ROMs could be 
selected via a software switch. If one wanted DECB it had to 
be copied into a 2764 EPROM. The Super Controller had a 
unique "Mini ExpansionBuss" (MEB) where several add-ons 
could be attached without the need for a MPI. This is 
probably the feature that sold more Super Controllers than 
any other aftermarket controller. A full range of add-ons 
including a real-time clock, EPROM programmer, 80 col- 
umn card for CoCo 1/2, a parallel port, an RS-232 port, and 
a hard drive adapter were eventually made- with most still 
available today. A Super Controller II (described later in 
this section) and a Mini Controller (introduced in 1989) 
were also made by Disto. The later contained only two ROM 

sockets (with provisions for a 24 pin ROM) and no MEB. It 
was shorter than the SC or SCII, like the Tandy FD-502. 

There was yet another odd disk system marketed for the 
CoCo, the Amdek Amdisk-III. This was the first small 
floppy disk system- the disks were only three inches in 
diameter. The disks were also more protected as they were 
in a hard plastic case. The Amdek disk resembled the newer 
3.5 inch disks available today, but there was no metal "shut- 
ter" over the case slot... a jacket was still required. The only 
problem with the Amdisk was the disk size. Amdek wisely 
used the standard Radio Shack disk controller, but one still 
needed a standard 5.25 inch drive. The Amdisks' biggest 
feature was price- it came with two drives, two blank disks, 
and a controller for only $599 (introduced in 1983). A key 
feature of the system was that both sides of the two drives 
were accessible, giving 624K of storage capacity. These 
weren't very popular with CoCo owners due to the non- 
availability of software on the small disks. The Amdisk was 
only advertised in Rainbow in 1983- it didn't take them long 
to realize CoCo owners weren't biting! A side note is that 
Amdek DID find a niche market for their three inch disks- 
many typewriters and dedicated word processors used the 
Amdek instead 3.5 inch drives, and some still do. 

When OS-9 came out a flaw was quickly discovered in the 
Tandy disk controller (and all others made at that time). 
Although OS-9 was a multi-user, multi-tasking true DOS, 
the CoCo disk controller was not! The controller used a 
simple design that interrupted the 6809 during disk access. 
This was the cheapest and easiest way to build the control- 
lers, but it prevented OS-9 from doing anything until disk 
access was completed. To alleviate this problem, Sardis 
Technologies introduced a "no-halt" controller late in 1987. 
This "smart" controller used a RAM cache to speed up disk 
operation and limit halting of the 6809 while retaining full 
compatibility with the Tandy controller. Under DECB halt 
mode was used while under OS-9 no-halt operation was 
allowed. This controller sold for about $50 more than 
comparable disk controllers. Why so late before one of 
these became available? OS-9 wasn't very usable for multi- 
tasking/user operations with just 64K in the CoCo 1 & 2. 
With the 512K CoCo 3, faster operation became desirable 
to increase productivity. Sardis had dropped out of the CoCo 
market by the next year. 

Disto also introduced a no-halt controller, the Super Con- 
troller II, just a month or two behind Sardis. The SCII was 
priced about the same as the Sardis controller, but had the 
features of the original Super Controller as well (four 
ROMs- one could now be a 24 pin- and mini expansion buss), 
which made it more attractive than the Sardis model... not to 
mention the respect which Disto products had earned. 

There is something strange about the disk controller's I/O 
address in the CoCo's memory map. The disk controller is 
addressed from &HFF40 to &HFF4F. This means that the 

Tandy's Little Wonder 

page 71 

SCS line activates the controller, as the SCS line area is 
&HFF40 to &HFF5F. Note that the entire area isn't used by 
the disk controller, just half of it. When Tandy designed the 
CoCo it intended only one item to be in the expansion port 
at a time. Therefore, they allowed whatever was written in 
this I/O area to completely fill it. What happens is that a copy 
of whatever is in one half "ghosts" to the second half also. 
This causes problems when a second hardware device (such 
as a hard drive controller) attempts to use the I/O area from 
&HFF50 to &HFF5F, as the signal "ghosts" up into the area 
used by the floppy controller. The MPI was designed to 
allow more than one device at a time. It fully decodes the 
SCS I/O area so that ghosting is prevented. So does the X- 
Port and Slot Pak (see Expansion Devices). Y cables have no 
circuitry to do this, so will not work with certain devices. 

Naturally, CoCo users have found a cure for this situation! 
The address area can easily be fully decoded by adding a 
74LS32 (quad OR gate... only one gate is used) to intercept 
the SCS signal and OR it with the A4 address line. Connect 
as follows: 1) Bend all EXCEPT pins 7 & 14 of the 74LS32 
straight out from the sides of the chip. 2) Place this chip on 
the back of any other 14 pin 74xxxx chip in the controller and 
solder pins 7 & 14 to the same pins of this chip. Make sure 
the notches in the ends of both chips are lined up! 3) Solder 
a jumper between pins 4, 5, 9, 10, 12, 13, & 14. This sends 
power to the unused inputs, forcing them high and preventing 
possible problems later (pins 6, 8 & 1 1 can remain uncon- 
nected). 4) Locate land 36 (SCS hne) on the edge of the 
controller that plugs into the CoCo. Cut the trace from this 
pin with a razor knife just after the wide land stops. Solder a 
short piece of wire to the land, being careful to leave enough 
room for the controller to push in the CoCos' connector. The 
other end of this wire should be soldered to pin 1 of the 
74LS32. 5) Find out where the trace that was cut from land 
36 goes on the controller (it will be slightly different 
depending on the controller part number). Solder another 
piece of wire from this point to pin 3 of the 74LS32. 6) 
Locate land 23 (A4 address line) on the same end of the 
controller. Solder a short piece of wire to that land also (DO 
NOT cut the trace!). The other end of this wire goes to pin 2 
of the 74LS32. The controller should now work properly 
with a Y cable. 

All other CoCo floppy controllers will require this opera- 
tion also. Even the Disto Super Controllers need this modi- 
fication to work with a Y cable. On the Super Controller (and 
possibly the J&M controllers with built in parallel port) this 
modification renders the mini-buss expansions unusable, as 
they are decoded in the &HFF50 to &HFF5F area. To use the 
mini-buss, a Slot Pak, X-Port, or MPI MUST be used, as they 
re-supply the necessary decoding. 

Now a word about floppy disk drives themselves. Early 
Tandy drives are most often made by TEC (Tokyo Electric 
Company).. These are full height units notorious for not 
staying in alignment (as are many early floppy disk drives). 

Most aftermarket suppliers stuck with higher quality Tandon, 
Shugart, or TEAC models (Tandy later switched to Shugart 
drives, and other manufacturers). Most full height units 
provided by Tandy were capable of reading only 36 tracks 
with a seek access time no faster than 12ms (access time is 
the amount of time , measured in millionths of a second - ms- 
it takes the read/write head to move from one track to 
another). The old TEC units may not work faster than 20ms. 
The only full height drive supplied by Tandy that will read 40 
tracks is the white cased unit. Nearly all single sided half 
height drives, whether supplied by Tandy or another vendor, 
are capable of accessing 40 tracks and most will work at 
6ms. The FD-502 drives are all double sided 40 track. 

The best thing about CoCo disk systems is that the drive is a 
standard model available almost anywhere computers are 
sold. Any 360K 40 track double sided drive will work, 

and should be used for replacing older full height and single 
sided drives. These drives are available used for as little as 
$20-$25 in most areas. Many IBM people have upgraded to 
higher capacity drives and no longer want or need these 
drives. Check with local computer shops if searching for a 
drive. The old full height drives were quite power hungry 
when compared to newer models, so two half height drives 
will work nicely in one of the old full height cases. 

Was 360K mentioned in the previous paragraph as the drive 
capacity? DECB only supports 35 track single sided opera- 
tion (156K), but the drive mechanicals are otherwise iden- 
tical to the double sided 360K units. There are several DECB 
enhancements that allow accessing the full 40 tracks and the 
"back" sides of these drives. All configure the "front" (nor- 
mal single side) as drives and 1 and the "back" as drives 2 
and 3. If only one double sided drive is used, it can be 
configured as drive and 1. The back sides can also be 
accessed by using some memory location POKEs (see 
"Color BASIC"). The connectors on the drive cable will have 
to be replaced with new ones (#276-1564) if there are teeth 
missing, as the contact for position 32 (missing from "pulled 
teeth" cables) is necessary to switch to the back side. Only 
three physical double sided drives can be connected to a 
CoCo controller because all follow the Tandy convention of 
using position 32 as drive select 3 (necessary to maintain 
software compatibility). Drive number selection is made 
with a "shunt" on the oldest drives (one is NOT likely to find 
a drive with a shunt in use today!), by the more common 
jumper block one newer ones. Once the connectors have all 
their teeth, the drives must be configured for position. This 
is done by placing a jumper over the pins marked "DSx", 
where "x" is the position desired (note that some drives are 
marked 0-3, others A-D). Shunts had metal jumpers that 
were initially all connected; the drive desired would be 
broken. Changing configuration meant replacing the shunt. 
There are two simple hardware modifications that allow 
accessing the back of a double sided drive; one to the 
controller, another to the drive (only one or the other is 
necessary). The modifications are fully reversible. This is 

page 72 

Tandy's Little Wonder 

not recommended unless it is laiown tliat OS-9 will not 
be used, as OS-9 can use the drives as single 360K units. If 
one owns a set of full height drives by all means keep using 
them provided they are reliable and meet ones needs. If any 
problems, replace them with double sided 40 track drives. 

DRIVES: This is perhaps the easiest of the two modifica- 
tions to accomplish. All that is needed is a SPDT toggle 

1. Cut the trace on the disk controller circuit board between 
land 32 of the drive cable connector end and the rest of the 
circuit board (use a sharp razor knife to cut the trace). 

2. Solder a wire to the land (32) and another to the other side 
of the land. Solder another wire to ground (all of the bottom 
drive cable connector lands are grounded). 

3. The wire on land 32 should be connected to the center pole 
of the switch, the other two to either side. 

4. The switch can be mounted in a hole drilled in the top shell 
half Make sure enough wire is used so that the shell can be 
easily separated and the circuit board removed. 

5. Reinstall disk controller. When the switch is in one 
position, the normal side of three double sided drives is 
active. In the other position (grounded) the "back" sides are 
accessed. The confusing part is that both the front and back 
of the same drive will be accessed by the same drive number! 

TION: This method is a little harder, but more rewarding 
since it operates with no user interaction other than select- 
ing a drive number. All that is needed is a 74LS08 (quad two 
input AND gate) and a 1 6 pin socket (all wiring is done to the 
socket, not the chip... socket can be eliminated). It is recom- 
mended that the number corresponding to the side of the 
drive be marked on the drive itself for easy recognition. 

1. On the socket, attach a 4-6 inch piece of wire to pin 1, 2, 
3, 14, and 15. 

2. Tie pins 8, 9, 11, and 12 to pin 14; pin 14 to +5V (position 
1 on the drive power connector). 

3. Tie pins 4 & 5 to pin 2. 

4. Solder the wire from pin 1 to land 32 on the cable 
connector. DO NOT cut the trace on the drive! 

5. Connect the wire from pin 6 to the drive select line for the 
normal side of the drive on jumper pin closest to drive cable 
connector. Connect the wire from pin 2 to the drive select 
for the "back" side (DSO and DSl makes the normal side 
drive 0, back drive 1). The usual method is to use DS & 1 
with a single drive, & 2 and 1 & 3 with two double sided 

6. Connect the wire from pin 3 to any drive select on the 
jumper side across from the drive cable connector. 

7. Connect pin 7 to ground (anywhere on the drive frame) 

8. Once all connections are made to the socket, firmly press 
the 74LS08 into it. Mount the chip upside down to the drive 
frame with double backed foam tape (picture hanging tape), 
being sure to place it where it won't touch the case sides or 
interfere with other drives. 

9. Install drive in case and plug into disk controller. It should 
now operate as if it were two single sided drives. If not, go 
back and check your work! 

Although the standard CoCo drive is the 156K or 360K 
5.25", 35-40 track unit, the disk controller will also 
support 5.25" or 3.5" 720K, 80 track drives. Simply plug 
the drive into the cable along with the other drives! Unless a 
modified DECB (such as ADOS) is used, only the first 35 
tracks and one side will be available (the previous modifica- 
tions will work on these also). OS-9 comes with drivers that 
allow full use of these drives. The 5.25" units were made 
obsolete when IBM skipped over them in favor of the 3.5" 
720K drives. The ill-fated Tandy 2000 adopted the 5.25" 
drives, as well as several other non-IBM type systems before 
IBM started using 80 track models. The best thing about the 
5.25" drives is that they can be "double stepped" (the head 
moved two tracks instead of one) to read (but NOT write!) 
standard 5.25" disks. OS-9 and ADOS provide for double 
stepping. OS-9 users will benefit most from these drives, 
especially if a hard drive is not a viable option due to cost or 
other reasons. 1.2MB and 1.44MB floppies can't be used. 

Hard drives were first made available to CoCo users by 
Software Support in early 1984. These were five megabyte 
units and sold for $999.95 for a complete system! Sure is a 
good thing that prices have come down dramatically, but that 
is the major reason that hard drives have really been an elite 
peripheral for most CoCo users. Even now, complete CoCo 
hard drive systems cost around $350 for a 20MB system. 

Cost is not the only problem with hard drives for some users. 
Hard drives work very well with OS-9. Tandy even realized 
that OS-9 needed a hard drive when it introduced it's own 
hard drive adapter in 1985. Disk BASIC is another story. 
DECB was designed to be a simple floppy disk system, 
period. It was never intended to handle the file structure 
necessary for proper hard drive operation. The systems that 
do work with it partition the drive into as many as 255 virtual 
156K floppy drives and patch DECB to recognize as many 
drive numbers. It is up to the user to keep up with what is on 
each virtual drive! This isn't as bad as it sounds... it can be 
viewed as having up to 255 directories, each directory 
limited to 156K. Most DECB hard drive programs have 
some type of menu system that allows at least a one line 
entry for each virtual floppy. 

Something must be said about the Tandy Hard Disk Inter- 
face (26-3145)- under no circumstances try to use it! 

This has got to be the worst thing Tandy EVER produced for 
the CoCo! No aftermarket hardware or software is usable 
with the thing. Tandy provided drivers for OS-9, but never for 
DECB. The worst problem is that the interface and software 
will only support old style Tandy hard drives which are no 
longer available, were slow, and if found used are not likely 
to last long. Only 10MB, 15MB, and 35MB hard drives were 
available for use with this interface. These drives had custom 

Tandy's Little Wonder 

page 73 

built in controller boards and were originally made for the 
Model I-IV computers. 

The most known hard drive system still available is one built 
around a Burke&Burke CoCoXT adapter. This adapter fits 
between a Multi-Pak Interface, Slot Pak, or Y cable (modi- 
fied to supply external power.. . the CoCo can't power a hard 
drive controller!) and a standard half card PC/XT eight bit 
hard drive controller. This system is one of the fastest 
available for the CoCo. 

With new eight bit PC/XT controllers falling in price to the 
$40-$50 range and smaller 20MB-60MB hard drives falling 
rapidly in price, many CoCo users are now looking at hard 
drives. Used controllers and drives are readily available for 
$200 or less simply because PC owners no longer need or 
want them. It is getting increasingly difficult, if not impos- 
sible, to find new 20MB-40MB hard drives! The 
Burke&Burke interface comes with OS-9 drivers. A soft- 
ware package for DECB users (Hyper I/O) is sold separately 
for $30. A typical Burke&Burke system would price as: 

CoCoXT Interface 

New 8 bit controller 

Refurbished 20MB hard drive — 
Case and power supply (surplus) 

Hard Drive Cable Set 


- $75 


■ $75 



All new equipment would add another $50+ to this price. 
Two reasons are apparent that make a CoCo hard drive 
system so costly- the need for an interface converter (in this 
case the CoCoXT) and the external case and power supply. 
Together these add up to nearly half the cost of the entire 
system ($150). Today's hard drives don't require a lot of 
power. An old full size floppy drive case will happily power 
a small half height hard drive (especially if it is a 3.5" unit) 
AND a half height floppy without overheating. 

The second best known hard drive set-up uses a Disto hard 
drive adapter- either in a Super Controller or MPI adapter. 
The Disto adapter is designed for use with an SASI (Shugart 
Associates System Interface... pronounced "sassy") or an 
SCSI (Small Computer System Interface... pronounced 
"scuzzy") type controller. These controllers are getting hard 
to find now. The following controllers can be used: 


Western Digital WD1002SHD Adaptec 4000A 

Xebec 1 4 1 OA Adaptec 4070 DTC 520 series 

All but the 4070 use standard "MFM" type hard drives, the 
4070 uses an "RLL" type drive. 

Most currently available SCSI drives have built in (embed- 
ded) controller boards, meaning they do not require an 
external controller between the Disto interface and hard 

drive. The only problem with this arrangement is that most 
newer SCSI drives only support the PC standard of 512 byte 
sectors. The driver software that comes with CoCo adapters 
requires 256 byte sectors. Only Seagate "N" (numbered as 
"ST157N") and Rodime 650 series drives are known to 
support 256 byte sectors (all have embedded controllers). 
HardSoft offers an OS-9 driver that supports 512 byte 
sectors, meaning almost any SCSI drive can be used. DECB 
is not supported as of this writing. 

Other hard drive systems include: 

* Owl-Ware - This system supports almost any SASI and 
SCSI controller or embedded drive (with 256 byte sectors). 
The Omti 5200 controller, which also supports high speed, 
no-halt floppy drives under OS-9, is fully supported. Hard 
drive works under DECB with drivers from Owl (Hard Drive 
BASIC 3) and Burke&Burke (Hyper I/O for Owl). The 
floppy system works ONLY under OS-9. A Tandy type 
floppy disk controller is still required for DECB support 
with the Omti 5200 floppy system. 

* Ken-Ton - The Ken-Ton interface is the best true SCSI 
interface available for the CoCo. It also supports SASI 
controllers. RGB-DOS is available for DECB users, as well 
as drivers for OS-9. 

Prices vary depending on the size drive and type of control- 
ler, but should be similar to new equipment Burke&Burke 
prices. A good source for small, inexpensive hard drives is 
AAA Disc Drive Repair 1464 Madera Road Simi Valley, 
CA 93065 (phone 805-523-9495) At the time of this writ- 
ing they had ST125N SCSI drives (20MB, refurbished, 15 
month warranty) for $125 and floppy drives for as little as 
$25 (same warranty). Call or write for current pricing. 

3. Printers 

The CoCo comes equipped to operate a serial printer, not the 
more common parallel type. Serial devices transmit data one 
bit at a time, over as few as three wires for a printer. Parallel 
devices transmit data over a minimum often lines one byte 
(eight bits) at a time. Though the speed of parallel transfer is 
fixed, it is usually faster than serial transfers. Parallel rates 
depend upon the speed of the computer and printer. 

Serial transfer speed varies from as little as 120 bps (bits per 
second) to as fast as 19,200 bps on the CoCo. With no 
alterations, serial data is transferred at 600 bps. Note that 
bps and the tenxi "baud" are usually used interchangeably. The 
serial transfer rate can be changed by poking a different value 
in memory location 150 (see appendix). 

Many Tandy/Radio Shack printers were made with connect- 
ing to the CoCo in mind. These have a four pin serial port as 
well as a parallel port (in most cases). Most are switchable 
between 600 and 2400 bps and serial/parallel operation, 
making them usable on all Tandy/Radio Shack systems 
(including IBM compatibles). In the Tandy/Radio Shack 

page 74 

Tandy's Little Wonder 

numbering system, an "LP" model is a Line Printer (early dot 
matrix), "DMP" a Dot Matrix Printer, "DWP" a Daisy Wheel 
Printer, "CGP" a Color Graphics Plotter (or ink jet in the 
case of the CGP-220), and "TP" a thermal printer, which also 
uses dot matrix technology but with special heat sensitive 
paper instead of a ribbon. 

Dot matrix types are the most prevalent, as they can print 
graphics as well as text. All but the LP series, CGP-1 15, TP- 
10, and DMP- 105 through 120 models are capable of 
correspond- dence quality text printing, which is slower but 
neater than standard (draft) output. The most common printer 
today is the nine pin dot matrix, though 24 pin models are 
quickly becoming the standard. Generally, the more wires 
the better the print, though the nine pin printer is adequate for 
most uses. A daisy wheel printer is slow, but produces 
typewriter quality output- they use the same daisy wheels as 
typewriters, and are essentially typewriters with no key- 
board. Indeed, many high-end typewriters have serial ports 
built in or available as options. 

The following list of Tandy/Radio Shack printers have the 
four pin connector built in. All are nine pin and support the 
IBM graphics character set unless otherwise noted. A couple 
of the printers were made to use with the CoCo only. The 
ribbons for some of these may be next to impossible to find 
in stock (note that the DMP- 107 was the last advertised to 
work directly with the CoCo, in 1991). Radio Shack will 
order ribbons for you, no extra charge or minimum order, 
for many of their printers. Catalog numbers for ribbons were 
Usted in the 1993 catalog (thermal paper for TP-10): 

Cat.# Printer Notes Ribbon 

26-3020 (all) 6' CoCo/MC- 10 Printer Cable (4 pin) n/a 
26-1167 LPVII 9", 30 cps, 7 pin, Tandy graphics 26-1424 
26-1168 LPVIII 9", 80cps 26-1418 

26-1261 TP-10 4"thermal paper, 8 pin,CoCo only 26-1332 
26-1275 TRP-100 9"thermal ribbon, battery/1 lOV 26-1297 
26-1193 CGP-1 15 4.5", 12 cps, Inkjet (3 black) 26-1480 
(color set: 1 ea. red, green, blue) 26-1481 
26-1268 CGP-220 9", 37 cps, ink jet (black) 26-1281 
(color set: 1 ea. red, green, blue) 26-1281 
26-1253 DMP-100 9", 50 cps, 7 pin, Tandy graphics only. 

26-1276 DMP-105 9", 80 cps, 7 pin, Tandy graphics only. 

26-2802 DMP- 106 9", 80 cps 26-1288 

26-2821 DMP-107 9", 100 cps 26-1236 

(3 pack) 26-1238 
(color set: 1 ea. red, green, blue) 26-1235 
26- DMP-110 9", 50cps, 8pin 26-1283 

26-1255 DMP-120 9", 120 cps, Tandy graphics only. 

26-1280 DMP-130 9", 100 cps, Tandy graphics only. 

(DMP-130A, msmae specs) 26-1235, 1236, 1238 

26-2814 DMP- 132 9", 100 cps 

26-2815 DMP- 133 9", 160 cps 

26-1254 DMP-200 9", 120 cps, Tandy graphics only. 

26-2812 DWP-230 15", 20 cps 26-1458 

(3 pack) 26-1445 
26-1251 DMP-400 15", 140 cps, Tandy graphics only. 

26-1277 DMP-430 15", 180 cps, 18 pin 26-1296 

26-2808 DMP-440 15", 300 cps 26-2809 

Other printers have add-on serial interface boards. Virtually 
any printer (or typewriter) with a serial interface may be 
connected to any CoCo. A special cable will be needed, as 
the standard for serial devices is a DB-25 25 pin connector. 
Just connect the lines as follows. The functions are listed 
just in case the printer in question does not use a DB-25, 
such as the PCjr, serial printer (a once popular surplus item, 
this was a thermal printer that required special paper, which 
is still available at large office supply stores, or fax roll 
paper may be used). 

CoCo DB-25 

Pin # Function Pin # Function 

2 Receive Data 20 External Ready 

3 Ground 1 (or 7) Ground 

4 Transmit Data 3 Receive Data 

Serial printers are becoming harder to find, though they are 
still being made. The following printers have serial inter- 
faces built in. Prices were average mail-order selling as of 
January 1993. 

Alps Allegro 500, 216 cps, 24 pin, 9", $350 * 
Alps ASP 1600, 192 cps, 9 pin, 9", $235 * 
Brother M-1809, 360 cps, 18 pin, 9", $340 
Brother M-1909, 360 cps, 18 pin, 15", $450 
C.Itoh Pro Writer C-510, 240 cps, 24 pin, 9", $270 
C.Itoh ProWriter C-240, 240 cps, 9 pin, 9", $300 
C.Itoh ProWriter C-245, 240 cps, 9 pin, 15", $390 
Cidzen 200-GX, 240 cps, 9 pin, 9", $225 * 
Citizen 200-GX15, 240 cps, 9 pin, 15", $275* 
Citizen GSX-130, 180 cps, 24 pin, 9", $310 * 
Cidzen GSX-140, 192 cps, 24 pin, 9", $325 * 
Citizen GSX-145, 192 cps, 24 pin, 15", $450 * 
Epson LX-810, 200 cps, 9 pin, 9", $250 * 
Epson FX-850, 220 cps, 9 pin, 9", $265 * 
Seikosha SP-2000S, 192 cps, 9 pin, 9", $210 
Seikosha SL-230AI, 277 cps, 24 pin, 15", $460 
Seikosha SP-2415, 300 cps, 9 pin, 15", $300 

* Includes the cost of an optional serial interface board, but 
not installation. These boards add from $50-$ 100 to the cost 
of a printer, plus installation (unless installed by purchaser... 
requires opening printer case and plugging in a small expan- 
sion board in most cases). 

Tandy's Little Wonder 

page 75 

Most laser and ink-jet printers also have serial interfaces 
built in. These usually cost in excess of $500, more than 
most would want to put into a printer for a CoCo! If one 
already has a laser or other serial capable printer, by all 
means connect it! Most CoCo software supports the Epson/ 
IBM graphics standards, so any printer emulating an IBM or 
Epson model should work nicely. Cer-Comp's word proces- 
sor is the only CoCo program known to have a laser driver. 

Apple printers are usable as is (a special cable may have to 
be made, and some features may not be accessible by 
software), but Commodore 64 printers ARE NOT! The 
Commodore uses a unique serial interface not compatible 
with other computers. 

There is a better, usually cheaper, and much more versatile 
way to connect a printer to your CoCo- through a serial/ 
parallel converter. These devices convert the serial data 
signals to parallel compatible signals, as well as converting 
the connectors as well (parallel printers normally use a 
"Centronics" 36 pin connector rather than a DB-25). Radio 
Shack sells a serial/parallel converter (26-2889, $99.95) 
that has a DB-25 on one side, a Centronics connector on the 
other. A cheaper solution is a converter specially made for 
the CoCo. Several manufacturers continue to make these 
interfaces (Metric Industries, Blue Streak, etc.). Some of 
the current hardware vendors carry these priced from $40- 
$65. Some printers provide +5V on pin 15 of the Centronics 
connector, others don't. Those that don't will have to be 
modified to provide this voltage (solder a wire from any +5 V 
source inside the printer to pin 15... make SURE this pin IS 
NOT GROUNDED FIRST!... if it is grounded, disconnect 
from the circuit board by cutting before adding +5V) or an 
external power supply will have to be purchased, adding $6- 
$15 to the total converter cost. 

By using a converter, the printer can be used with almost an 
computer, and the converter can be kept if a newer, more 
capable printer comes along later. The CoCo serial/parallel 
converters can also be used with other computers by making 
a special cable, as the CoCo type converters use the CoCo 
four pin serial input instead of a DB-25. 

Some manufacturers made parallel port cards for the CoCo. 
All suffered from the fact that BASIC had to be patched in 
order to use them. Both J&M and Disto disk controllers 
supported parallel ports with their modified DECB ROMs. 
Disto also supplied drivers usable under OS-9. Only the 
Disto parallel ports are still available, but require either a 
Disto Super Controller or a MPI and adapter. 

4. Expansion Devices 

When Tandy first came out with the CoCo, they envisioned 
it as a beginner/game machine. If one got serious about 
computing, they should buy a more serious (Tandy) com- 
puter. Only one expansion port, the game cartridge connec- 
tor, was included. Needless to say, Tandy under estimated 
the market and the CoCo, and users soon wanted to install a 
disk drive, RS-232 Pak, and still be able to plug in the latest 
game cartridge- without tearing the system apart first! 

Tandy introduced the four slot Multi-Pak Interface (MPI) 
in 1983 to cure the limited expansion offered with only one 
port. Just before the MPI was released, in October of 1982, 
Basic Technology introduced it's own answer to the expan- 
sion problem, a five slot expansion buss on a cable. At one 
time, there were three to five expansion bus devices avail- 
able for the CoCo. It is not advisable to use any of these with 
a CoCo 3, as addressing may conflict with memory areas 
used by the GIME. All were discontinued by 1986. 

Any MPI slot could contain a ROM Pak game. To choose 
between them, one merely turned the MPI off and then 
moved the numbered switch on the front of the MPI to the 
desired pak. The disk drive controller is normally used in 
slot 2 or 4, and the RS-232 Pak in slot 1 or 3. A hard drive 
controller would reside in slot 2 or 4 also, whichever the 
disk controller was not occupying (location depends on 
particular setup). Only the CTS (cartridge select), SCS 
(spare cartridge select), and CART (cartridge select inter- 
rupt) are switched between the pairs of slots- all other lines 
are always connected to all four (CART and CTS are switched 
together). The reason for this is that the CTS and SCS lines 
are used to activate devices with a ROM in them. Only two 
such devices can be used in the MPI at any one time. The 
other pair of slots must contain a device (such as the RS-232 
Pak) that doesn't use the SCS orCTS lines for port decoding. 
The Speech-Sound Pak, Modem Pak, and RS-232 Pak (and a 
few others) contain internal circuitry that tells the computer 
where to find them, while the disk controller (and others that 
rely on SCS/CTS slot switching) doesn't. 

Slots can be selected by software also. This is done by 
POKEing a value in location &HFF7F. Once memory loca- 
tion &HFF7F has been written to, the hardware switch is 
deactivated until the MPI is reset or turned on after being 
turned off It is best to leave the hardware switch on the slot 
the disk controller (normally slot 4) is in when the computer 
is first turned on. The hardware switch must be used to select 
a ROM Pak in a slot when a disk controller is left in the MPI. 
The following values are used to determine which slots the 
CTS/CART and SCS lines are switched to: 

1 &H0 &H0 

2 &H10 &H01 

3 &H20 &H02 

4 &H30 &H03 

page 76 

Tandy's Little Wonder 

To change all three signals to a slot, add the two values 
together. For all three in slot one: POKE &HFF7F,&H0O; 
for all three in slot two: POKE &IffF7F,&Hll, etc. To 
place CTS and CART in slot two, SCS in slot four POKE 
&HEF7F,$H13 (value SHIO + &H03). Note that there are 
enough bits in the control byte to allow up to 16 slots. The 
most ever used in one device was six (by PBJ Slot Pak and J- 
NOR Industries User 80C). 

CoCo to MPI: 

SCS- secondary chip select signal (FP40-5F) 
CTS- cartridge enable (8000/COOO-FEFF: 32K/16K ROM 
pak... used for device selection under OS-9). 
MPI to CoCo: 

CART- cartridge interrupt, connected to FIRQ via PIA, or 
FIRQ/IRQ viaGIME. Enabled from slot which also 
has CTS selected. 

There were two different versions of the MPI made. The 
large MPI (1025"x8.5"... 26-3024) was the firsL It was 
initially marketed in a "Mercedes Grey" case to match the 
CoCo 1. With the introduction of the CoCo 2 later in 1983, 
a matching white cased unit was made available. The second 
version, a smallw unit (approximately S.S'xT.S"... 26-3124) 
due to a reduction in circuit board size, was introduced late 
in 1985. A custom 64 pin chip in the small unit took the place 
of nine separate chips in the large. 

The coming of the CoCo 3 late in 1986 caused a few 
problems for the MPI. The oldest (grey) MPI stored a copy 
of the slot select address (&HFF7F) at another address 
(&HFF9F- the address older MPI manuals recommend 
POKEing to fcH" slot selection). This was not a problem on 
older CoCos because they did not use &HFF9F for anything- 
the CoCo 3 uses it as part of its video horizontal-offset 
register. Any time this address was written to by the CoCo 3, 
the older MPI switches away from slot 4, where the disk 
controller normally resides. Subsequent writes to this ad- 
dress would fiirther confuse the MPIs slot select circuitry, 
thus preventing normal operation with a CoCo 3. The solu- 
tion is to buy and install an upgraded PAL chip (U8), which 
is fortunately socketed (the ONLY socketed chip!) and 
currently available from FARN A Systems and possibly from 
Tandy National Parts. 

Some of the newer large white MPI and all the small MPI 
units appear to work fine with the CoCo 3, but there is still 
a minor problem. The reason these MPIs seem to work 
acceptably is that the address at &HFF7F is not copied to 
&HFF9F, so the slot select circuitry is not inadvertently 
changed. Problems arise when attempts to read data from 
ports of the GIME chip between location &HFF80 and 
&HFFBF are made. The MPI was designed before the GIME 
was conceived, and thinks these memory addresses are 
available for general input/output operations. The data buff- 
ers in the MPI are therefore opened when an attempt to read 

these GIME data ports. This means that both the GIME and 
MPI are trying to access the data bus at the same time, which 
can garble the data being read from the GIME ports. Using an 
un-upgraded MPI with a CoCo 3 WILL NOT damage either 
device, but software may not work correctly at times, caus- 
ing quite a few headaches and uncontrollable results. 

Again, the solution for the large MPIs is to replace U8 with 
an upgraded PAL. The newer, small MPI requires a different 
an)roach due to the custom chip, which is soldered in place 
and unalterable. The data buffer enable circuit must be 
modified to prevent the MPI from opening its data buffers 
when the GIME addresses are in use. The fix involves 
mounting a 74LS10 NAND gate chip on a small piece of 
circuit board (a 14 pin socket may also be used). Wire as 
shown below. Make sure the circuit board is mounted so that 
it cannot move about inside the MPI, possibly causing a short 
circuit (if using a socket, place a piece of double backed 
foam tape on the chip, then stick upside down on top of 
another chip oc the circuit board). 
tiore: trace BerwGc-H Pn) i^oFtCi >*mo P/i^I ^2. of 
IC ^ (oh Mpr eiraa-.T Bo/lED> MOST 6B Cor. 


+5Vfrompinl6ofany IfipinIC 



GND from pin 8 of 
any 16pinIC 


-j~ 0. 1 mf d ceramic 
disk capacitor 



To pin 52 




[AJMultl-Pak Interface. Connects up to four Program Pak" 
cartridges lo your Color Computer at once! No more plugging 
in and unplugging cartridges. Connect disk drives and other 
accessories, too. Change between slots with selector switch 
or under program control. U.L. listed. 
26-3124 99.95 

Tandy's Little Wonder 

page 77 

OS-9 poses a few additional constraints on MPI use. Place- 
ment of devices in particular slots is mandated by OS-9 
device driver software, device decoding, and if the device 
needs to send a CART interrupt back to the CoCo. 

The RS-232 or Modem paks need to get an interrupt line 
back to the 6809 inside the CoCo. Therefore, they must be 
in a slot selected for the CTS/CART lines before the inter- 
rupt can get through. Since only one slot can do so at a time, 
you have two different drivers, ACIAPAK and MODPAK. 
ACIAPAK sets up for an interrupt from slot one, and 
MODPAK instead uses the VIRQ timer to check regularly 
(called polling) for an interrupt register flag in a fully 
decoded device in slots two, three, or four. 

So, if a device fully decodes itself (like the Speech-Sound 
Pak), it can go in any slot. If it uses the SCS to enable it (like 
the disk controller), or needs to use the CART (like the RS- 
232 pak, which is fully decoded), it must go in the slot that 
the SOFTWARE decides. Note also, that you cannot use 
more than one device that fully decodes itself at the same 
address, since such a device is slot-independent in that 
respect and ALL of them will turn on at the same time- a 
mess! So you can't use two RS-232 paks, for instance, unless 
they are internally re-wired for different addresses. Some 
aftermarket RS-232 paks have jumpers so that an alternate 
address can be selected. 

The RS-232 Pak is easy to modify (by design) to a different 
address. It comes decoded for FF68-6B. It is easily changed 
to be decoded for FF6C-6F though. /T2 and ACIAPAK can 
then be used for the original in slot one and /M2 and 
MODPAK for the readdressed one in slot two or three. 
Rewiring is this easy: 

1) Cut the trace running from pin 8 of the 74LS04 (U6) to pin 
2 of the 6551 (Ul). 

2) Solder a wire from pin 9 of U6 to pin 2 of UL 

That's it! The use of the A2 address line had to be low before, 
now it has to be high. The disk controller address can also be 
changed, see "Mass Storage" for details. 

Why aren't all devices fully decoded? Cost is why. It's 
cheaper to make a disk controller that uses the already 
decoded SCS line from the CoCo, than to include the one or 
two extra chips needed to decide it's own address. Theoreti- 
cally, it also meant you could have a disk controller in each 
slot and pick between them, but that isn't really practical. 
Many OS-9 Level II users (CoCo 3 ONLY) have found it 
necessary to "strap" the CART line between all four slots. 
This is done by soldering a jumper wire under the MPI circuit 
board between the CART pins (pin 8) of all four slots. This 
keeps the RS-232 pak from locking up or loosing characters 
during operation, and allows more than one device to send an 
interrupt to the CPU without switching slots. 

The RS-232 will sometimes loose characters or lock up in 
a CoCo 3 due to the way the GIME chip detects the CART 
signal. The GIME detects a CART on transition from high to 
low of the interrupt line. If one interrupt occurs directly 
after another, the GIME never sees the second one. This 
situation can easily occur when using an RS-232 Pak under 
OS-9, as an interrupt is generated each time a character 
comes into the RS-232. At the same time, the GIME is 
generating 60 interrupts per second. Sooner or later one 
interrupt follows another to close and a character is lost or 
the RS-232 Pak locks up. 

A Schottky barrier diode (#276-1165) must also be added 
inside the CoCo 3 to complete the fix. The anode of the 
diode (lead opposite the stripe) should be connected with a 
length of wire (24 or 26 gauge) to resistor R2 (4.7K ohms... 
the part reference numbers are printed on the circuit board). 
This resistor is located near the reset button. Solder the wire 
on the end of the resistor farthest away from the reset button. 
The other end of the diode, the cathode (end nearest the 
stripe), should be connected with a length of wire to resistor 
R7, which is located near the PIA (40 pin chip near the 
opposite comer of the board as the reset button... "kitty 
corner" from reset). Solder the wire to the end of R7 nearest 
the PIA. Insulate the diode and all bare areas of the wire well 
to prevent shorts on the circuit board. This modification 
bypasses the GIME interrupt and connects the CART line 
directly to the IRQ (interrupt request) pin of the 6809. The 
diode prevents interrupt signals from feeding back to the 
CART line. If a Schottky barrier diode is not available, a 
more common 1N34 germanium diode can be used. Silicon 
diodes CANNOT be used, they could cause logic problems. 
The only DECB program known to use interrupts when using 
an RS-232 Pak is Ultimaterm (a popular share-ware terminal 
program). Otherwise, only OS-9 users need to consider this 

The only problem with strapping the CART line is that auto- 
execute ROM cartridges and expansion devices would cause 
a crash of the system. The solution is to either cut the trace 
to or tape over ("scotch" tape will work fine) the auto-exec 
land (land 8.. usually the first one from the left-bottom of the 
card edge) of the cartridge, thus preventing automatic ex- 
ecution. One then types EXEC &HE010 to execute the 
cartridge. Note that devices other than game ROM Paks, the 
Tandy RS-232 Pak, and Tandy DC Modem Pak that auto- 
execute are extremely rare. 

In OS-9 Level I Version 2.0 (which will run on a CoCo 3), 
you are expected to power up using the slot in which you have 
your disk controller. CCDisk does NOT set the MPI SCS 
latch. However, ACIAPAK assumes the RS-232 pak is in 
slot one and the disk controller is in slot 4, as it stores a $03 
at FF7F. CCHDisk, when it needs to access the Tandy Hard 
Disk interface (which uses the SCS line), changes the MPI 
select to $02 (CART from slot one, SCS to slot three). So 
the HDI must be in slot three. In both cases, the RS-232 or 

page 78 

Tandy's Little Wonder 

Modem Pak that you wish to be interrupt-driven by ACIAPAK 
must be in slot one. CCHDisk clears D.DMAFlg when it's 
not using slot three, so CCDisk "knows" the SCS is going to 
slot four when it wants to shut off the motors after a time- 
out. That is, the disk controller had BETTER be in slot four! 
If CCHDisk is using the MPI latch, it sets D.DMAFlg so 
CCDisk will reset it's time-out counter and try again later. 
Drivers that change slots should use this flag byte. Some 
third-party drivers, most notably the ones by Brian Lantz for 
Disto and J&M, don't use this flag. In the case of the Disto 
paks, since they are slot-dependent- these drivers shut off 
interrupts while accessing the hard disk or RAMdisk, while 
the SCS slot is changed. This is probably in the mistaken 
belief that drivers can be time-shced (a common miscon- 
ception) and some other might change slots. There's no 
reason to do this, unless there is an IRQ-driven device that 
will change slots on you. None are known to do that. Most 
third party hard drive interfaces (except the Disto, as noted 
above), also need to reside in slot three when using OS-9. 
The mentioned slot assignments are usually used by conven- 
tion even on Level II systems. 

CCHDisk and ACIAPAK can be easily patched to use a 
specific slot for the RS-232 pak. The bytes to change are at 
offsets $80 in ACIAPAK, and offsets $4D7 and $4E9 in 
CCHDisk (if you use it). Currently, these bytes are set to 
$03, $02, $03. Change the zero ($0x) to whichever slot code 
you desire for the RS-232 pak, re-verify the modules, and 
you're done. For the RS-232 pak (using ACIAPAK driver) in 
slot three, change them to $23, $22, $23, for example. 

Tandy discontinued the MPI in 1989. This left the market 
open for vendors to come up with a way to allow more than 
one cartridge to be plugged in at one time. Howard Medical 
introduced the Slot Pak II in December of 1989. This device 
is packaged in the equivalent of an old long disk controller 
shell (about six inches long), leaving enough room outside 
the CoCo case to mount three cartridge connectors. A 
support is glued under the shell for stability. The original 
SPII was powered by the CoCo itself or an external wall 
transformer, which was necessary for devices which re- 
quired +/- 1 2 V. The SPIII has an integrated power supply, as 
the CoCo 3 does not have sufficient capacity to power more 
than one external device without over heating. It also has a 
switch which allows use of a ROM Pak game cartridge in the 
center slot without unplugging all cartridges. Some ROM 
Paks do not seem to work properly though- it would be best 
to unplug all devices except the disk controller and ROM 
Pak then transfer the ROM to disk if possible, or unplug the 
SP for ROM Pak use. Due to the possibility of dislodging the 
SP from the CoCo (and subsequently blowing the 6809), it 
is best used with a keyboard extension cable of some sort. 
Slots one and two of the SP function similarly to the MPI 
slots. Slot one uses the bits for MPI slots one AND three, 
slot two for MPI slots two and four. Only one of the bits is 
necessary to set the slot value though. This was done so that 
if software was hard coded to use slot four, the three slot SP 

would still function correctly. The CART line IS NOT 
switched by the SP at all, it is "strapped" between all three 
slots- similar to the modification described earlier (the 
diode still needs to be installed inside the CoCo 3 though). 
The third slot DOES NOT have the CTS or SCS connected at 
all. This means that only devices NOT decoded in the range 
of &HFF40-&HFF5F and WITHOUT on board ROMs can 
be used there. This slot was intended for an RS-232 Pak, 
though others meeting the previous criteria work also (Tandy 
Speech & Sound Pak, most MIDI adapters, etc.). 

In the same issue of Rainbow (December '89), Orion Tech- 
nologies introduced their "XPort", also a three slot MPI 
replacement. This device worked identically as the Slot Pak, 
with two switchable slots and one fixed. The main difference 
was that the XPort had a fifteen inch ribbon cable between it 
and the CoCo. This allowed moving the XPort away from the 
CoCo.. the keyboard could easily be pulled closer to the 
user, greatly reducing the possibility of blowing the 6809 
and the need for an extended keyboard. The XPort also had 
its own power supply built in from the start. Unfortunately, 
Orion is no longer in business. 

In 1992, a new company appeared to support the CoCo with 
hardware... CoNect. They provide two expansion devices- 
the "XPander" and a"Y Box". The XPander plugs into the 
cartridge connector and provides two SCS driven ports as 
well as a third port for fully decoded cards. The third port can 
also be used for ROM cartridges with the flip of a switch. The 
XPander is designed to fit in a modified CoCo case or used 
for repackaging in a PC type case. Another feature of the 
XPander is a built in RS-232 port which is compatible with 
the Tandy RS-232 Pak. The Y Box is a fully buffered Y cable 
(more reliable and longer than a Y cable alone). A powered 
version that supplies +/-12V is available (required by 
Burke&Burke hard drive systems). 

One other expansion device bears mentioning.... the simple 
Y cable. This is nothing more than a short piece of ribbon 
cable with two 40 pin connectors on it. Anyone capable of 
soldering can easily make a Y cable. Get a 44 pin card (#276- 
154) and cut four of the lands off one edge. Trim it down to 
a comfortable length (about one inch). Get a 40 conductor 
ribbon cable no more than six inches long. Now get two 40 
pin crimp-on card edge connectors (44 pin types can be 
used, just tape over the last two positions). First separate the 
wires (about one inch) on one end. Strip enough of each to 
solder onto the positions on the shortened card. Now take a 
good look at the shortened card lands. Notice that they 
alternate between the top and bottom lands on the board. 
Take a good look at the crimp-on connectors. One side is 
offset so that the contacts actually alternate from one side to 
the other. The ribbon cable should alternate also so that the 
lands top of the card match the top contacts of the connec- 
tors and vice-versa. Once the positions have been lined up, 
solder the cable to the card. Plug this into the CoCo. Cut the 
ribbon cable so that it will just touch the surface of the work 

Tandy's Little Wonder 

page 79 

surface. Crimp one connector on the end and the other up 
just enough so that a second device will rest on top of the 
first. The cable should be only three to four inches in length. . 
the shorter the better! Y cables usually work well with a disk 
controller and RS-232 Pak. Using two devices that contain 
a ROM or use the SCS and CTS lines requires changing the 
address location of one of the devices (see "Mass Storage" 
for modifying the disk controller address, "Expansion De- 
vices" for modifying the RS-232 Pak). A good way to disable 
a ROM is to cut the leg from the chip across from pin number 
one (cut the power pin). Note also that some devices require 
12V power, which would have to be supplied from an exter- 
nal source for CoCo 2 and 3 models (make sure the 12V 
DOES NOT go into the CoCo cartridge connector!). 

5. Miscellaneous Devices 

Many more items have been made over the years that allow 
the CoCo to do many specialized jobs. The most prevalent 
are listed below. Two items not listed are modems and RS- 
232 paks. These are discussed in detail under "Telecommu- 
nications" elsewhere in this book. Only one modem, the 
300bps DC Modem Pak (#26-2228), was made specifically 
for the CoCo. 

* Joysticks - Three different joystick designs were made 
for the CoCo by Tandy. The first was a very simple one button 
stick (#26-3008). They were housed in a black case and sold 
in pairs for $ 1 9.95. All can be said is that they are better than 
nothing! The second design was much better- the Deluxe 
Joystick (#26-3012). This stick was switchable between 
self-centering and free-floating action (the first are free 
only). Two "fire" buttons are used, though only one works on 
the CoCo 1/2, both on the CoCo 3. These sticks were made 
by Kraft, and also connect to the 1000 series of IBM 
compatibles (note that the similar appearing IBM sticks are 
wired different- they WILL NOT work with the CoCo or 
1000 series). They may still be available in some stores, but 
are not listed in the 1993 catalogs. Only the last stick design, 
the #26-3123 Pistol Grip model, was listed in 1993. This 
stick features two buttons on the base plus a trigger and 
thumb button on the stick. The stick buttons work the same 
as the two base buttons (only two active inputs). Like the 
Deluxe stick, these also work with the 1000 series. A Hi-Res 
Joystick Interface (#26-3028) was also available for the 
CoCo 3. This gadget plugged into the cassette and one 
joystick port and increased the resolution of the joystick, 
making for smoother action. Unfortunately, special soft- 
ware was required and little of this was made. The last 
versions of CoCo Max3 (a popular paint program) and Max- 
10 (a graphic, Mac/MSWindows type word processor) re- 
quire the Hi-Res Interface. 

* Mouse - Tandy came out with a CoCo mouse not long after 
the CoCo 2 was introduced. The original mouse (#26-3025) 
featured only one button since the CoCo 2 supported no 
more on the joystick port. A two button mouse, the Deluxe 
Color Mouse (#26-3125), was introduced along with the 

CoCo 3. These mice plug into the joystick port and act just 
as the joystick does. An OS-9 driver for a serial mouse is 
available on Delphi (see "Telecommunications") orFARNA 
Systems (requires an RS-232 pak- the CoCoPRO!/DC Mo- 
dem Pak conversion won't work). 

* Video Digitizer - Two companies made popular video 
digitizers forthe CoCo. The Micro Works DS-69 "Digisector" 
was the most popular. A later model, the DS-69B, is similar 
to the original (sometimes referred to as the "A" model) but 
faster. Neither are currently available. An Australian com- 
pany still produces the "Rascan" Digitizer (updated and 
renamed "DigiSector", available from FARNA Systems), 
which is the faster of the listed models. These are not "frame 
grabbers"- they don't pick a moving picture from a video tape 
or TV set. They require a still subject, as they take 15 to 30 
seconds to fully digitize a picture. They don't digitize text 
either, just pictures. These devices are similar to the ones 
found in malls and amusement parks making "computer 

* Plug 'N Power Appliance/Light Controller - Two 

models of this X-10 compatible home controller were 
made. The first plugged into the cassette port (#26- 1 1 82) of 
a CoCo or Model I/III. This came with a cassette program, 
and may be usable on the CoCo 3, but they are extremely rare 
devices now! The second model (#26-3142) came out with 
the CoCo 2. It can still be picked up new, but attaches to the 
serial port and CANNOT be used with a CoCo 3 . The reason 
is that it comes with ROM-Pak software that won't load on 
the CoCo 3 because a "semi-graphics" mode of the CoCo 2 
is used. This mode is not supported on the CoCo 3 due to 
limited use- the Plug 'N Power is nearly the ONLY thing to 
use that mode! It might be possible to use the IBM compat- 
ible Plug 'N Power or X-10 controller (serial version), but 
software would have to be written for it. 

* Orchestra 90 CC - This was a six octave, five voice stereo 
music composing cartridge with built in ROM software 
(#26-3143). It could be connected to a stereo for output. 
Some music files can be downloaded from Delphi (see 
"Telecommunications"). Created music can be stored on 
tape or disk (with a MPI). 

* Sound/Speech Cartridge - This thing would actually 
make your CoCo talk (#26-3144)! A few games supported 
this cartridge... very few! It came with instructions for easily 
programming speech. 

* A-Bus - This is a general purpose control system for the 
CoCo and a number of other computers as well. Each 
computer had a special adapter that connected to a special 
five slot A-BUS board. Up to five of these could be intercon- 
nected, making 25 slots available. A full range of devices for 
process control, robotics, data acquisition, monitoring and 
sensing, and motion control were available. Software was 
not supplied- this was an experimenter's system! This item 

page 80 

Tandy's Little Wonder 

is still available from the manufacturer (Alpha Products, 
242-W West Avenue. Darien, CT 06820... phone 203-656- 
0756). If the special CoCo adapter is no longer available, 
their RS-232 adapter can be used for serial port connection 
to the CoCo. 

• MIDI Synthesizer Interface - Several units were once 
available, but only two are currently produced. The first, and 
probably most known, is the MusicWare CoCo MIDI 3 and 
CoCo MIDI Pro systems. Both consist of software that 
functions like a studio recorder, and a MIDI interface adapter 
that plugs into an MPI or Y cable (required). Multiple tracks 
can be recorded and played in real time. CoCo MIDI 3 runs 
on any CoCo with at least 64K. A four minute, nine voice 
recording will consume about 95% of memory and require 
approximately 45K of disk space. Disk files can be linked to 
play in sequence. CoCo MIDI Pro requires a S12K CoCo 3 
and has additional memory capacity as well as other added 
feamrcs. MIDI 3 records 10 tracks, MIDI Pro 16. This is an 
update of the popular Lyra system. 

The second MIDI system is the Kala Software UltiMusE III 
and UltiMusE/K systems. The first runs under OS-9 Level II, 
the second under OSK. Both are virtually the same except 
for the platforms they run from. Actually, the only hardware 
involved is a special cable that ccmnects to the serial port 
(schematics included to build cable, or purchase from Kala 
ready made). Records up to 16 tracks. May be a little harder 
for a non-OS-9 user to set up (OS-9 version uses VDG 
screen), but has the advantage of not requiring an MPI. 

Many more items have been available at one time or another 
for the CoCo. The best source for information on unusual 
finds would be Rainbow and other CoCo magazine back 
issues, especially 1984 to 1986 issues. A few will not be 
compatible with the CoCo 3, but all should work (to some 
degree) with the CoCo 1 and 2, unless they require 12V 
which is not provided by the CoCo 2 (unless an MPI is used). 


Hardware Upgrades and Modifications 

The following upgrades and modifications are the most 
common. Note that disk drive, Multi-Pack, and monitor 
upgrades and modifications are covered imder "Peripherals". 

ROM Upgrades 

ROM upgrades aren't really necessary in most cases. Re- 
placement ROMs are still available from some dealers, 
though they may be hard to find. There were three versions 
of Color BASIC- 1.0, 1.1, and 12. The only one that really 
needs changing is 1.0. 1.0 used a seven bit printer driver 
instead of the more common eight bit (Tandy only had a 
seven bit printer at the time). This ROM won *t print graphics 
without a special, no longer available, printer driver pro- 
gram . Version 1 . 1 allowed use of a full 64K, and version 1 .2 
cleared a few minor bugs in 1.1 and the BASIC interpreter 
was re-written to run slightly faster. All NC board CoCo 1 
and TDP-100 models will have 1.1 or 1.2 ROMs, all CoCo 
2s 1.2 OT 1.3. If a new ROM is desired, try to get the 1.3 
version (#8040364C... 1.2 is #8040364B, 1.1 #8040364A, 
1.0 #8040364). If there is an empty socket on a CoCo 1 or 
2 next to the Color BASIC ROM, then Extended BASIC is 
not present The catalog number for the required 24 pin ECB 
ROM kit is 26-3018 (includes ROM and new manual... part 
#AXX7072 fOT the ROM only). 

The "A" and "B " model CoCo 2s require a single 28 pin ROM 
that has both Color and Extended BASIC in it. A set of five 
jumpers near the ROM socket are marked 64K and 128K 
(the size of the ROM). If the computer came with Color 
BASIC only, the jumper wires will have to be cutand moved 
to the 128K positions. The easiest method is to trim the 
wires as close to the 64K pads as possible then bend them 
back to the 128K pads and solder there. These CoCo 2s also 
have a version 1 .3 Color BASIC ROM, but the only changes 
are for the SAM setup routine (required for these models... 
the 24 pin Color BASIC 1.3 ROM will also work in older 
CoCos) and the copyright notice. The part number for the 
128K ROM upgrade is MX-6436. These upgrade ROM kits 
are likely no longer available, but it will only cost 29 cents 
to write Tandy National Parts and find out. Make sure you 
know the catalog number of the CoCo that will be using the 
ROM. Tandy sorts parts lists by catalog numbers. 

The version number of the highest level BASIC ROM is 
displayed on screen when a CoCo is turned on. Type the 
following to discover each version of BASIC: 

PRINT PEEK(41302)-48 - Color BASIC version 
PRINT PEEK(33023)-48 - Extended Color BASIC version 

Tandy's Little Wonder 

page 81 

RAM Upgrades 

Each of the various CoCo models were upgraded in a differ- 
ent fashion. All original model (gray case) CoCos can be 
upgraded to 64K, though the earliest models only supported 
upgrades to 16K officially. It just took some enterprising 
CoCo enthusiasts to figure out how to access additional 
memory once it was learned that the 6809 could actually 
address 64K. Each model is discussed separately, along with 
its' identification characteristics. 

Revision numbers are found on the right front side of the 
circuit board on the CoCo 1 models. All CoCo 2 boards are 
easily identifiable by the DRAM configurations. Each revi- 
sion of these boards is only slightly different from the 
others. All CoCos are most easily identified by their catalog 
numbers, though it is possible that a later board was installed 
in an older case when upgrading or repairing by a Tandy/ 
Radio Shack service center. In such a case, there should be 
a sticker on the bottom of the case stating which board was 
installed and what upgrade was done. 

Generic numbers have become common for DRAM. In the 
number "4 1 1 6- 1 2", the "4" indicates Dynamic RAM, the first 
"1" a one bit chip, and "16" the capacity in "K" bytes (IK is 
actually 1024 bytes, though this figure is usually rounded to 
1000). The "12" indicates the speed of the chip in hundreds 
of nanoseconds (ns, one billionth of a second, in this case 
120ns). Therefore, a""164-10" is a64Kxlbit, 100ns DRAM. 
If the second digit is a "4", the chip is a four bit chip. 
Remember that it takes eight bits to make up one byte, so two 
4464-10 chips makeup a complete 64K, whereas it takes 
eight 4164-10 chips. 120- 150ns DRAM should be used in 
all RAM upgrades. Less than 120ns (faster) DRAM chips 
will be slightly higher priced, but will also work just fine. 
Slower chips will overheat and eventually fail, causing inter- 
mittent problems as the computer heats up. Do note that the 
early CoCo Is did use 200ns DRAM. These were never 
intended to run at double speed, however, so the slower 
access time wouldn't normally cause a problem. At any rate, 
it is difficult to find chips rated at less than 150ns anymore, 
and the smaller chips (4K & 16K) are difficult to find at all. 

The Original CoCo (CoCo 1) 

IDENTIFICATION : Gray Case w/vents one the sides, 

"Chicklet" keyboard. 

CATALOG NUMBERS: 26-3001, 26-3002 


It IS NOT practical to upgrade these boards to 64K, though 
it is possible. A description of each board and reason for not 
upgrading follows. Many early CoCoist DID upgrade these 
boards, but with CoCo 2 computers selling for under $25 in 
most areas, it is not advisable nor cost effective to make such 
upgrades. If one must upgrade one of these machines, order 
a back issue of the May 1984 Rainbow from Falsoft ("RAM/ 
ROM Upgrade Roundup", pp. 49-51). Practical RAM up- 
grades are mentioned. 

Very few "C" boards were actually sold, so few that no 
attempt to upgrade them should be made- these are definite 
collector items! The C version was almost a prototype, with 
many wires and a small satellite board inside. 

The "D" board is quite similar to the C, but does not have the 
satellite board. Most 4K and 1 6K CoCo 1 s have the D board. 
This board would only work with 4K and 16K DRAM 
(generic number 4104 and 4116). Simply replace the 4K 
chips with 16K units. Next find the two jumpers marked 4K 
and 16K (one next to the 6883 SAM, the other between the 
two 6821 PIA chips) and move them to the correct position. 
The C board may not even be upgradable to 16K! 

"E" boards were the first to be upgradable to 32K. These 
require simply installing 64K chips in place of the existing 
1 6K units and moving the jumpers (one between U8 and U9, 
three next to the keyboard connector, and one just below 
C44) to the 32K position. Hmmm... 64K chips but only 32K 
RAM? That's correct! 32K was selected as the maximum 
supported RAM because Color BASIC couldn't use more 
than 32K anyway, and no other operating system was avail- 
able at the time. There never were any 32K DRAM chips 
made. 32K chips were made up by piggy backing 16K 
DRAMs, even commercially! Tandy got discount prices on 
half good 64K chips (half bad?). There is a jumper located 
near U29 marked HIGH and LOW. This selected either the 
upper 32K or lower 32K halves of the 64K chips (all the 
chips had to have the same half bad, Tandy just sorted them 
before installing). If new chips were purchased, it won't 
matter which half is selected. Later versions have all good 
64K DRAM as the supply of half-good chips dwindled. 

Why were there half-good chips to begin with? Manufactur- 
ing a chip on a silicon wafer is tricky business. Even now 
10%-20% of chips made are defective and must be thrown 
away because there is no way to repair them. The larger scale 
the chip integration (more components on a single chip), the 
higher the rejection rate. The supply of half-good chips dried 
up as manufacturing techniques improved. 

64K CoCo 1; TDP-100 

IDENTIFICATION : Beige Case, Low-profile keyboard, 

vents on sides (some early models came with CoCo 1 style 

cases and keyboards) 

CATALOG NUMBERS: 26-3002A, 26-3003A, 26- 

3004A, 26-3005 

BOARD REVISIONS: "NC" (also called "F" or "285"). 

This board either had "NC" or no revision marking at all. 
Many people refer to it as the "F" board because it cam after 
the D revision (why not the "E" then?... who knows!), or the 
"285" due to those numbers being the first in the number silk 
screened on the board. It is unclear what NC actually meant. 
The keyboard on these machines had full size square keys, 
but they were only about 1/4 inch tall, leading to the "low 
profile" designation. 

page 82 

Tandy's Little Wonder 

All that is needed to upgrade these boards are eight 4164 
DRAM chips, moving three jumpers from 16K to 64K 
positions, and adding another jumper (the pegs can be sol- 
dered together). The jumpers are located near U21 (2), U28 
(1), and U17 (the one that needs a jumper added). If the 
computer originally came with 16K, clip capacitors C58, 
C60, C62, C64, C66, C68, C70, and C72. These can just have 
one leg cut rather than entirely removed. It is not necessary 
to reinstall the capacitors even if 16K DRAM is put back in. 

The final Korean CoCo 2, the "B" version, could be upgraded 
in three ways: two 4464 chips, eight 4164s, or via the 
previously mentioned plug in board with eight 4164s. The 
best, and only known to exist method, is by using two 4464s. 
To use eight 4164s on the motherboard, sockets would have 
to be added to the blank spaces marked off for them on the 
motherboard (or the chips could be soldered in directly). 
NOTE: The 4464 chips removed from a CoCo 3 when 
upgrading to 5 12K can be used in an A or B model CoCo 2. 

American Made CoCo 2 

IDENTIFICATION : White case, vents on top. 
CATALOG NUMBERS: 26-3026, 26-3027 

There may be only one board revision that was produced. The 
only one the author has seen has "REV B" printed on the 
board. It is possible that an "A" version was produced, or 
maybe the "A" was just a prototype (like the CoCo 1 "A" and 
"B" revisions). The RAM upgrade is the same regardless. 
Remove the eight 4116 chips and replace them with 4164 
DRAM. Locate the two adjacent solder pads labeled "Wl" 
between U6 and U7 (near the center of the board). Solder a 
tiny piece of wire between the two pads and the 64K will be 
activated. Many people bend a short piece of wire in a "U" 
shape as it is easier to hold with a pair of tweezers or needle 
nose pliers while soldering. 

Korean Made CoCo 2 

IDENTIFICATION : Identified by DRAM type and ROM 
socket, and catalog numbers. 

CATALOG NUMBERS: 26-3134(A,B), 26-3136(A,B) 
BOARD REVISIONS: A and B revisions noted by RAM 
locations and catalog numbers. 

There were three different CoCo 2 boards manufactured in 
Korea. Tandy gave each a separate catalog number. The first 
were 26-3127, 26-3134, and 26-3136. 26-3127 came with 
ECB and 64K installed. 26-3134 and 26-3136 came with 
Color BASIC and ECB, respectively. These were upgraded 
by replacing the 4116 chips with 4 1 64s. In the front left hand 
comer of the board are two solder pads labeled "Jl" and 
"64K" (between R7 and R27, near IC7). Solder a jumper 
between these pads just as with the American made CoCo 2. 

The second Korean version added an "A" to the catalog 
numbers (26-3134A, etc.). This model uses only two 4416 
RAM chips. Upgrade by replacing with 4464 RAMS and 
soldering a jumper between the solder pads labeled "J6", 
"RAM SIZE", and "64K" (near IC4, front left comer of 
board). Notice the two white connectors on either side of the 
RAM chips? These were to support a plug in RAM board with 
eight 4164 chips if necessary. The availability and cost of 
4464 chips was questionable when Tandy first designed the 
motherboard. To the best of the authors knowledge no 
upgrades were ever made using that method. 

CoCo 3 

IDENTIFICATION : Has different arrow key location; Fl, 
F2, CTRL, and ALT keys 
BOARD REVISIONS: Only one board made. 

The CoCo 3 comes with 128K installed. This is made up by 
four 4464 DRAM chips. There are two white connectors 
near the four RAM chips. These are for a 512K upgrade 
board. Before installing the board, pull the four 4464 chips 
out and clip capacitor C65. Several 512K upgrades were 
made, all using 41256 (256Kxlbit) DRAMs. 

Disto made a 1MB upgrade that plugged into the 512K 
upgrade sockets, required a bit of soldering to the CPU, had 
16 41256 chips on board, and had sockets for an existing 
512K board. This took up quite a bit of room inside the 
computer, made it run hotter, and wasn't exactly easy to 
install. Many OS-9 users loved the extra memory regardless 
of the difficult installation. 

Just recently, Disto announced a 2MB upgrade. This board 
uses two lMBx8bit SIMMs (Single In-line Memory Mod- 
ules... the "three chip" variety) and plugs right in. The only 
soldering required is replacing the CPU with a socket (which 
the 2MB board plugs into; there is a socket for the CPU on 
the 2MB board). This is a much neater installation! One 
should note that these boards were designed with the OS-9 
user in mind. Programs for DECB can be written to take 
advantage of the added memory, but only ADOS is known to 
use any memory over the standard 5 12K, and then only for 
RAM disk use. The 1MB and 2MB boards will also fiinction 
as if they were 512K upgrades under DECB. 

The MMU (Memory Management Unit) inside the GIME 
chip is capable of addressing up to 2MB, but is two control 
bits short to access that much RAM. Tony DiStefano (the 
designer of the boards) added one bit on the 1MB board and 
two on the 2MB board with external circuitry. The problem 
with DECB use of the additional RAM is that the GIME 
doesn't track the contents of these added bits and therefore 
can't read them. Any DECB applications must store the 
contents of these two bits so that the GIME can move around 
the extra RAM without crashing the computer. OS-9 handles 
memory differently and does not require the GIME to track 
the two added bits. 

Tandy's Little Wonder 

page 83 

Beyond 64K in the CoCo 1 & 2 

There were several 128K CoCo 1 & 2 upgrades introduced 
in 1984. All suffered the same fate- not enough support or 
utility to really be used. The main problem with these 
upgrades was that they had to move large chunks of memory 
(either 32K or 64K) to maintain compatibility with existing 
software (this was also due to the memory map of the CoCo). 
All of these upgrades actually "banked" or "paged" through 
the large memory chunks. Some had the 32K ROM area 
stationary and the 32K RAM area was switched, others (the 
more useful with existing software, actually) switched the 
entire 64K memory block in and out, ROM and all. 

A machine language program was usually required so that a 
POKE switched between memory banks. The one exception 
was the Dynamic Electronics upgrade, which had a toggle 
switch to page between two banks of 64K. This proved to be 
a bit more useful, as two m/1 programs that changed the ROM 
code could be loaded and switched between. This setup was 
designed so that two documents could be edited at once 
using Telewriter 64 by switching the two banks. There was no 
way to copy text between the two banks, however. The POKE 
method worked well with BASIC programs, but m/1 pro- 
grams couldn't be switched without crashing. 

The main problem with these upgrades was that they never 
caught on. Drivers were never written for OS-9 to take 
advantage of the extra memory, indeed, it may not have even 
been possible! Due to the programming restrictions of these 
upgrades (another reason they weren't very popular), they 
are not recommended. If one is interested, articles on how 
to build them were printed in the following magazines: 

Rainbow, DEC 1984, "128K The Easy Way", pp. 162-168 
HOT CoCo, SEP 1985, "The Fat CoCo" (256K),pp. 28-31, 
program listing pp. 46-49 

The Rainbow issue is still available from Falsoft as a back 
issue order, the Hot CoCo article may still be available from 
the publisher. See "Library" for addresses. 

The only practical way to use memory over 64K in these 
machines is by using a RAM disk. This uses RAM memory 
to emulate a disk drive. A RAM disk is very fast, but one must 
remember to copy or backup anything in the RAM disk to a 
physical floppy before turning off or resetting the computer. 
Most RAM disk software can set the RAM drive as any 
number, making it useful for games that load different parts 
as needed. Several were made at one time, though none, 
accept possibly a Disto unit, are available today. A proj ect to 
build a RAM disk appeared in the SEP, OCT, and DEC 1 989 
issues of Rainbow (in three parts- all three needed), which 
are available as back issues from the publisher. 

Upgrading tlie Keyboard 

The original CoCo had a "chicklet" keyboard with small 
square keys. It was functional, but didn't look or feel like a 
"real" keyboard. "Professional" keyboards made their ap- 
pearance on the CoCo market in 1983 to replace the chicklet 
model. These plugged right into the CoCo in place of the 
normal keyboard. The first was a re-wired Model 1 keyboard 
provided by Spectrum Projects in 1983. This was closely 
followed the same year by Key Tronic, Micronix, Mark Data, 
and HJL, the later being the most known. Looking at the 
CoCo keyboard schematic, it is easy to see that there is room 
for four additional keys. All of the replacement keyboards 
had these keys on them. The keys could be programmed for 
special uses, but no programs for the CoCo 1 or 2 were 
written to take full advantage of them. 

The next CoCo keyboard appeared from Tandy late in 1983. 
Did Fort Worth take notice of all the replacement key- 
boards? Maybe not, but the CoCo 2 and 64K CoCo 1 were 
introduced with a new full travel, low profile, typewriter like 
keyboard. The keys were only about 1/4 inch tall (thus "low 
profile"), but typing was much easier and faster. This key- 
board was later supplanted (1985) by a "deluxe" keyboard 
with 1/2" tall keys slightly angled to make typing even easier 
and faster yet. 

The CoCo 3 was introduced with a keyboard similar to the 
CoCo 2 deluxe model, but with four additional keys (CTRL, 
ALT, Fl, F2) added. The arrow keys were also moved to the 
right in a diamond pattern, and the BREAK key was coded to 
provide an ESCape (control C) signal when shifted. The 
additional keys were functionally equivalent to the added 
keys of the aftermarket keyboards mentioned earlier, so 
those boards work well with the CoCo 3 . The keys will be laid 
out different though. An interesting side not is that the 
original CoCo 3 keyboard was laid out just like most of the 
aftermarket boards- with two extra keys on each side of the 
space bar (with a gap between SPACE and the added keys). In 
fact, a good number of those keyboards were made for 
Tandy, enough that they were sold through Radio Shack as 
surplus for $5 each in early 1985, when the final design was 
decided on. 

All early CoCo keyboards used a ribbon cable and in-line pin 
connector to attach to the motherboard. All "285" (or "F") 
board CoCo 1, TDP-100, CoCo 2, and CoCo 3 keyboards 
have a mylar film connector. The early CoCo required an 
adapter (no longer available) for use of a mylar strip key- 
board, and vice-versa. The keyboard connector on a CoCo 2 
or 3 can be replaced with an in-line pin connector for use of 
an early type keyboard. The female mylar strip connector 
may still be available from Tandy (part #AJ-7567). This 
connector was made by Amphenol (AMP, #193910680A or 
#19391 1090A) and might be found at large supply houses. 
This connector can be installed in a CoCo 1 or used to make 
an extended keyboard. A ready-made keyboard extender 
cable is available from Hawltsoft (see vendors). 

page 84 

Tandy's Little Wonder 

Tandy made the CoCo and its' keyboard all in one case to save 
money. The CoCo can't always be put in the most comfort- 
able position for typing though, especially with an MPI 
attached (and there is the possibility of moving the MPI 
enough to blow the 6809!). The simple solution to this 
problem is to extend the keyboard away from the CoCo. This 
can be easily done with up to six feet of 1 6 conductor ribbon 
cable and a suitable connector on each end. 16 conductors 
will probably have to be removed from a 25 or more conduc- 
tor cable (#278-772 is a five foot, 25 conductor cable). 

A single row, PCB mount, male in-line pin connector can be 
inserted into the mylar strip connector. A matching connec- 
tor can be purchased for earlier model CoCos. The connec- 
tor for the mylar strip is a little more difficult. It may be 
possible to order one from Tandy National Parts as previ- 
ously noted. One could de-solder the keyboard connector 
from the CoCo motherboard and replace with a single row, 
PCB mount, male in-line pin connector, using a matching 
female connector on the ribbon cable. An easier approach is 
to use a 34 position card edge connector (a disk drive cable 
connector, #276-1564). This works well but requires a 
heavy piece of cardboard behind the mylar strip. Also note 
that the mylar strip only makes contact on one side. If using 
a crimp on type connector, remember that every other pin 
goes to the opposite side of the connector. Simply place the 
strip in the connector with the two unused pins on one end. 

Most people use a DB-25 connector mounted on the CoCo 
case and cable to connect to the CoCo rather than plugging 
straight into the motherboard. This leaves several extra 
wires that can be used to mount a remote reset button, LED 
indicators, etc., on the keyboard case. If using the original 
keyboard, cut a piece of thin plywood or hardboard, sheet 
metal, or heavy cardboard to cover the hole left by the 
removed keyboard. This makes an ideal mounting location 
for the DB-25 connector. 

What to use to house the keyboard? Many CoCo hackers use 
the original CoCo case, either as is or cut down in size, 
preferring to mount the motherboard in a separate case with 
the drives and MPI or other expansion device (see "Putting 
It All In One Case"). A nice looking case can be made from 
two pieces of plywood. Cut a keyboard size hole in the top 
piece and use a spacer material of suitable thickness around 
the edges, making sure there is enough space for the connec- 
tor and support for the edges of the keyboard. The flat ribbon 
cable can be laid between the top and spacer sections, firmly 
holding it in place. It is suggested that the top be screwed 
down to facilitate removal if necessary. If making a wood 
case, leave two and a half to three inches of blank space 
below the space bar for wrist support. You hands will thank 
you! Room can also be left to either side for a numeric 

Adding an extended keyboard cable is the perfect time to 
consider adding a numeric keypad, since the CoCo is open 
anyway! HJL used to make a number keypad, but one can 
easily be made by examining the keyboard layout on the 
schematic. Single pole momentary on or keyboard switches 
(mechanical switches... most IBM clone keyboards use 
electronic "Hall effect" switches that WILL NOT work) can 
easily be wired to the same points that the keyboard number 
switches are wired to (row pin 6, then pins 9- 1 6 for 0-7, row 
pin 7, pin 9 & 10 for 8 & 9 on keyboard connector). 

Why not add some additional keys also? A shift lock key is 
easily made by wiring a push on, push off switch between the 
two SHIFT keys (pin 8 and 16 of the keyboard connector). 
What about those often used shifted keys (+, =, *)? They can 
be made single stroke keys on the number jack (or alone) 
simply by using a double pole momentary on switch wired to 
press both keys at once. This type switch may be difficult to 
find in the shape of a key. An old keyboard cap may have to 
be removed, modified, and glued to the top of the switch. 
Tony DiStefano described using a transistor along with a 
single pole momentary switch to simultaneously "press" two 
keys at once in the April 1985 Rainbow (still available as a 
back issue at time of printing). 

The Hitachi 6309 CPU 

There is another processor that will work in place of the 
6809- the Hitachi HD6309 ("HD" designates Hitachi as the 
manufacturer). This chip has been around for some time, and 
is pin for pin compatible with the MC6809. At first, the only 
reason to use it was that the computer ran cooler than with 
the original 6809. The reason is that the 6309 uses CMOS 
(complimentary metal oxide silicon) construction, which 
consumes less power than standard NMOS (negative metal 
oxide silicon) chips such as the 6809. 

When Motorola decided they had a need for a CMOS version 
of the 6809, they contracted with Hitachi to provide it, thus 
the compatibility between the HD6309 and the MC6809. 
Hitachi went one step further, however, and added six regis- 
ters and a number of new commands to the 6309. Memory 
moves could be made four times faster than with the 6809, 
and a 16 bit multiplication to a 32 bit product was also 
included, plus more! When a 6309 is installed in place of a 
6809, no difference in processing speed will be noted and 
there is no access to the added registers or instructions. 

The 6309 runs in a 6809 "emulation mode" when first 
powered up. "Native" 6309 mode is accessed through a 
special command. Some software written for the 6809 
times itself by the IRQ (interrupt request) and NMI (non- 
maskable interrupt) instructions. In native mode, the 6309 
reduces the number of clock cycles required by IRQ and 
NMI, causing these programs to crash. Changing stack 
pointers directly also causes a system crash. Anything in- 
dexed from the stack pointer goes to a different location, 
due to the added registers of the 6309. In DECB, disk drive 

Tandy's Little Wonder 

page 85 

functions, the PLAY and SOUND commands, and the TIMER 
function all use the interrupts for timing. Any use of the 
drives or these commands causes Disk BASIC to crash. 

There was a slight problem, however: Motorola did not 
authorize any improvements! Motorola wanted a work-alike 
in CMOS packaging, and that was all it authorized Hitachi to 
make. This led to no documentation for the advanced native 
mode of the 6309 being officially available. When a group 
of CoCo users started discussing possible faster processors 
to replace the 6809 on Internet (see Networks), a Japanese 
student volunteered the 6309 due to the added functions. 
When asked for additional information, he transcribed a 
detailed article from a Japanese trade journal describing the 
added registers and instructions. Details of the native mode 
were apparently leaked or discovered in Japan. 

With this new information in hand, Burke&Burke and 
Gale Force Enterprises (see Vendors) developed pack- 
ages for OS-9 Level II that take advantage of the new 
registers and commands to provide 10%-30% speed in- 
creases in program operation. These upgrades cost under 
$50 including the 6309. The only modification to the CoCo 
itself is the addition of a socket for the processor. Two 
editor/assembler packages were available to allow using 
6309 functions with DECB; a patch from CoCoPRO! to 
Tandy's EDTASM (now available from FARNA Systems) 
and a new editor/assembler (under development at the time 
of writing) by Cer-Comp. 

There is hope for Disk BASIC users also. The following 
program, written by Rick UUand (of CoNect) with the 
assistance of Art Flexser (Spectro Systems), puts the 6309 
in native mode and patches Disk BASIC 1.1/2.1 and the 
PLAY, SOUND, and TIMER commands for proper opera- 

5 REM 6309 Patch by Rick Ulland and Art Flexser 

10 POKE &H0300, &H11 

20 POKE &H0301, &H3D 

30 POKE &H0302, &H01 

40 POKE &H0303, &H39 

50 POKE &HD8AA, &H6C 

60 POKE &H9C55, &H69 

70 EXEC &H0300 

Change line 50 to "&HD7B7, &H6C" for Disk BASIC 1.0/ 
2.0 or ADOS. There will only be a slight speedup, maybe 
1 0%, in BASIC programs. Machine language programs could 
be sped up as much as 30% or more using the extended 6309 

A manual describing the 6309 extended machine language 
commands along with patches for a few programs is avail- 
able for download on Delphi or on disk from FARNA 
Systems. The biggest problem with using the additional 
6309 instructions is that code written to do so will require 
the presence of a 6309 and will not run on a 6809. 

Putting It All In One Case - The Ultimate CoCo Upgrade! 
Many CoCo users don't like having their system spread all 
over a desk. It doesn't look neat, there is a tangle of cables, 
and the possibility of moving the MPI and shorting out the 
CPU. Some bolt the bottom halves of the CoCo case and 
MPI to a piece of plywood and add an extended keyboard 
cable, while others repackage the CoCo, MPI or Y cable (if 
used) and disk drives all in one case, usually a surplus PC 
case, but homemade cases are used as well. These can be 
anything from a custom made sheet metal case to a wood 
case lined with aluminum foil (glued to the inside and ground 
to the motherboard to reduce RFI). Almost any old, obsolete 
computer case found at a salvage sale can be used. Since the 
CoCo 3 will drive a CGA monitor, even an old "luggable" PC 
case equipped with said monitor will work quite well (or a 
small TV screen can be substituted), or the BarSoft TTL 
monitor adapter can be used with a monochrome screen. 
Some older CP/M computers, such as the Tandy Model IV 
and IVP (IV is monitor, computer, keyboard, and drives in 
one case, IVP is a luggable); and Kaypro II, 4, and 1 models 
used composite monitors which may be adaptable for use 
with the CoCo. 

Before attempting to repackage your CoCo, please remem- 
ber to be careful! It is next to impossible to replace a 
damaged motherboard. It will take some careful planning and 
basic electronics and soldering knowledge, but it can be 
successfully accomplished. It may be a good idea to read the 
Peripherals, Upgrades and Repairs sections of this book 
for some hints and tips before continuing. 

The following is an account by one person who repackaged 
his CoCo successfully. Use it as a guide, be careful, and good 

ATCoCo - Putting it all in one Box By Mike Haaland 
Written: December 14, 1988 Updated: January 15, 1989 
Edited/added to by: F.G. Swygert, February 17, 1993 

This article is the procedure I have used in order to get the 
clutter of computer components off my desk and into a 
single PC/AT clone case. It has been put together and 
distributed to aid those CoCo owners who are tired of the 
mess to do the same. 

There are still a few problems for BASIC users. One is that 
the baud rate is thrown off. This can be adjusted by using 
different values for setting the printer baud rate (POKE 150, 
xx)- values other than those listed for BASIC. Experimenta- 
tion will determine the proper values. 

I (nor the author of this book) cannot take responsibility for 
any damage you may do to your system while attempting this 
project. The need for such a transplant depends totally on 
your own tastes. 

page 86 

Tandy's Little Wonder 

The nicest thing about the ATCoCo (CoCo in a full size IBM 
AT type case) is you have so much room for drives, expan- 
sion packs, etc.; and that your system will be nice and neat 
without the need of having cables running all over the place. 
In an AT size case you have room for: 

Three half-height disk drives 

A full or half-height Hard Drive 

The CoCo motherboard (main circuit board) 

An MPI (small... large may fit) 

Four Paks (fit in four slots of the MPI) 

This is what I have installed in my ATCoCo . If I can figure out 
how to get the modem in there, I'll put it in too! My system 
has been running this way since December 1988 with no 
problems at all. 


Before you can get started you will need: 

1) Suitable Case and Power Supply. This article assumes 
a full size (at least six inches tall inside) PC/AT clone case 
and power supply. Other cases, such as the more common 
PC/XT size, can be used but the actual installation will differ, 
as there is not sufficient room in a PC/XT case to put an MPI 
or Slot Pak on it's edge as described. The CoNect Xpander, 
however, doesn't require as much height and will easily fit 
inside an XT size case, or any case as little as four inches tall 
inside. Tower cases usually have enough room to mount the 
MPI on the bottom and the motherboard running up one side, 
90 degrees to each other. Check the size of your MPI before 
purchasing a tower case, as some mini tower cases may not 
have enough room for the MPI. In many cases, a Slot Pak or 
Y cable can be used where an MPI can't. Power supply 
connectors may differ. If in doubt, use a VOM to check 
voltages before connecting to a CoCo. A floppy only CoCo 
system needs about 40 watts, a hard drive adds another 1 5 W- 
20 W, so a 65W-100W p/s would be sufficient. 

2) A set of all the connectors on the back of the CoCo, 

both male and female, including the RGB connector if you 
are using an RGB monitor. Cable to extend the ports and 
male cable type connectors will also be needed. For the 
cleanest installation get the female chassis mount connec- 
tors that can be mounted to a plate on the back of the case. 
Alternately, get female cable type connectors and run the 
cables out the back of the computer. They will have to be 
labeled in either case. 

4) A short (4 to 6 inch) 40 pin extender cable that will go 
from the CoCo motherboard to the MPI/Slot Pak. You can 
make your own by removing the 40 plug on the motherboard 
and wiring a ribbon cable in its place, or get another 40 pin 
(a 44 pin with four positions taped over on one end works 
nicely) and solder the ribbon cable to the back of the 

5) A keyboard extender cable. See Upgrades for instruc- 
tions on making one, or locate a "Puppo" or "Eagle" IBM 
keyboard adapter. 

6) A VOM meter. 

7) The ability to use a soldering iron. 

8) GUTS To take the plunge! 


1) Make up the extender cables for the ports and check that 
they work properly. Each cable will need to be long enough 
to reach through the back of your case. 

2) Make the extender cable for the RGB plug. 

3) Make the necessary arrangements for connecting the PC 
power supply (see Power Supply Repairs) to the CoCo and 


1) Remove the CoCo motherboard and MPI from their 


2) Lay your CoCo motherboard in the AT case with the 
ROMPak slot facing away from the drives and the plugs 
facing the front of the AT case, as far back in the case as 

3) Mark where the four mounting holes on the coco are on 
the case. Drill out the holes in the case. You can either mount 
the coco with the plastic legs supplied with the case or build 
your own mounts using small blocks of wood or plastic 
under each hole. Keep the CoCo OFF the bottom of the case 
(about 1/8 to 1/4 inch ). This will give you enough room to 
run the port extension cables under the board, prevent shorts, 
and allow the power supply fan to cool the motherboard. It 
would be a good idea to place a piece of cardboard between 
the case bottom and CoCo as further protection from shorts. 

4) Put the MPI in the left hand front comer of the case with 
the slots pointing in and the card edge that connects to the 
CoCo towards the back. Put electrical tape over the compo- 
nents that may be easily shorted to ground on the bottom 
edge of the MPI such as D 1 . Again, a piece of cardboard 
between the MPI/SlotPak and case would be prudent. 

If you have a short extender ribbon connector for the 40 pin 
ROM Pak slot on the coco, you can see how easily you can 
connect the MPI to the CoCo. If you want to make up your 
own, you will have to de-solder the slot connector and 
remove it. Solder a ribbon cable where the connector was 
and the other end to the removed connector. Be sure pin 1 
goes to pin 1, etc. Make the cable no longer than necessary, 
a long cable will cause problems. This is where the CoNect 
Xpander or Y-Box will help, and installation will be easier. 

Tandy's Little Wonder 

page 87 

5) I cut a piece of sheet metal to mount all those extended 
connectors on. Cut out some of the PC card slot dividers for 
additional room and make a plate to mount the connectors on 
that covers the slot area. If using long cables only, just leave 
one of the slot covers out and run all cables through that slot. 

6) Plug everything together, connect to the power supply, 
and double check all the wiring. 

7) Mount the drives in their slots and hook them up to the 
power supply. 

8) Plug your various packs into the MPI. 

9) Go back and double check ALL connections. Make sure 
EVERYTHING is connected properly. Turn on the power 
supply and test the various peripherals. If everything checks 
out okay, you're done. If not, you know what to do if you got 
this far! 

The "Reset" switch can easily be wired to the CoCo reset 
button. Remember, you can't get to the original one now! 
Simply connect the wires from the case reset button to the 
two pins on top of the CoCo reset button. 

Now if you can, remove the plaque from you old CoCo 3 top 
cover, the one that says "TANDY 128K COLOR COM- 
PUTER 3" and mount that on the front of the new case (for 
the completed look!!). 


This text file reveals how several CoCo users (including 
myself and the author of this book) have repackaged their 
CoCos. No responsibility whatsoever is assumed for anyone 
following the procedure described above. If you mess up 
your CoCo, it's your own fault, not mine, the book author's, 
nor the publisher's. Just be careful, it has been done many 
times before, and good luck! 


There are usually three lights, a momentary reset button, a 
two pole (on/off) "Turbo" button, and a two pole key switch 
on most all PC type cases. If you have a hard drive you can 
easily use one of the lights to indicate drive access by simply 
finding where the drive access light pins are on your HD and 
connecting them to the appropriate light. This is a big help if 
you have used a slot behind the front cover to put your HD in. 


Most CoCo repairs can be made with only a basic knowledge 
of electronics and soldering. The hardest repair to make will 
require removing a chip from a circuit board, but even that 
isn't very difficult for the "greenest" novice to attempt. The 
CoCo is a relatively robust computer and will take lots of 
abuse that would damage most others. Remember the fol- 
lowing basics and repairs should be simple and even fun! 

You can wire the power on light by hooking +5 VDC from the 
power supply through a 100 ohm, 1/4W resistor and the 
other side to ground. The "Turbo" light can be wired to 
indicate double clock speed by using a 74LS 123 and 74HC74 
with the following schematic: 




E Clock 
(6809 pin 34) 

CLR B2 Al 
Ql CI RCl 


H +5V 

/ 620 ohms 


.001 mf 

E Clock 
(6809 pin 34) 

-| +5V 


330 ohms 

"Turbo" LED 

NOTE: Another LED (of a 
different color) can be added 
to pin 6 of the 74HC74 to 
indicate normal (slow) speed. 

It IS NOT the purpose of this section to cover detailed 
operation of the CoCo circuitry. Simple explanations are 
given when possible, some may seem (intentionally) vague. 
If you can't figure it out, DON'T TRY IT! For more 
detailed information, consult a CoCo Service Manual (may 
still be available from Radio Shack, ask a salesperson or call 
Tandy National Parts to order a service manual for the 
catalog number of the desired CoCo) or the Motorola 
MC6883 or 74LS785 (earher version was 74LS783) data 
sheet, as well as those for the other major components. 
Schematics are reprinted in the back of this book also. 

1) Before attempting a repair, observe the symptoms care- 
fully. It is extremely important to describe what is happening 
as completely as possible, especially when asking for help. 
Try substituting components if possible. Also remember to 
disconnect ALL peripherals before assuming there is a 
problem with the computer. A bad printer, joystick, disk 
controller, etc., could be causing the problem. Unplug EV- 
ERYTHING, then if the computer works right, plug items 
back in ONE AT A TIME and see which causes the failure. If 
asking for additional help, outline ALL the steps you have 
already taken. Help is readily available on Delphi. Leave a 
forum message to "ALL" or to "MARTYGOODMAN". Ifyou 
don't leave details as described above, that is the first thing 
you will be asked to do! ! 


page 88 

Tandy's Little Wonder 

2) Before touching any chips on a circuit board, make sure 
you ground yourself by touching something metal or the 
ground on the board first. Some chips are static sensitive, 
meaning that a good static electric jolt could damage them. 
Touch the case of the RF converter on the CoCo mother- 
board (the metal box), the bottom edge connector pins on 
peripherals that plug into the cartridge port. There is usually 
a wide band that runs around the edge of most circuit boards. 
This is the ground plane, and is a good area to touch first also. 

3) The right tools and supplies are needed to do the job! A 
CoCo repair kit should include the following tools, subject 
to the repairs being attempted: 

means go ahead and use it, otherwise get a vacuum remover- 
the purchase won't be regretted. 

Diagnostic utilities on disk are available from Delphi and 
FARNA Systems. The only problem with disk based diag- 
nostics is the disk drives could be the problem! It might be 
a good idea to transfer some of the diagnostic programs to 
tape (I can hear long time users, who have used tape storage 
before, groaning already!). Of course, the tape circuitry 
could be affected also. In that case, the only alternative is to 
find a Tandy Diagnostic ROM-Pak. Good luck finding one! 
They only tested up to 16K of RAM, but checked all other 
circuitry. All but the RAM test is usable on the CoCo 3 also. 

Necessary Items: 

Multimeter (VOM), three range (minimum #22-212) 

Precision Screwdrivers (#64-1948) 

Phillips and Plain Screwdrivers 

Needle Nose Pliers 

Soldering Iron, 15-30 watt (#64-2070, 25 W) 

De-soldering Tool (#64-2120 or #64-2098) 

Pointed Cutters (#64-1833) 

Silver Solder (#64-013 or #64-015) 

Paste Flux (64-021) 

Diagnostic Utilities 

Optional Items: 

Logic Probe with Hi/Low LEDs (#22-303)* 

IC Inserter/Extractor Set (#276-1581) 

IC Pin Straightener (#276-1594) 

Soldering Heat Sink (#276-1567) 

1/4" Nut Driver (a multi-tip screwdriver uses 1/4" hex bits, 

doubles as a nut driver) 

TV Tuner Cleaner (#64-3315) or Cleaner/Degreaser (#64- 


* A multimeter can be used for some logic probe applica- 
tions. Find a good circuit board ground, then test for a 
voltage for a high signal (usually +5V), OV for low. Some 
tests REQUIRE a logic probe! 

One might want to consider Radio Shack' s compact 1 4 piece 
PC tool kit (64-1972), which contains screwdrivers, chip 
extractor/inserter, nut driver, tweezers, and carry case in 
lieu of some of the listed items. 

4) The "destructive removal" method of IC removal 
should be used by all but accomplished hobbyists. Use 
pointed cutters to cut the legs off of a chip close to the chip 
body, removing the body after all legs are cut. Now grasp 
each leg individually with needle nose pliers and heat the 
solder joint, pulling out the leg. Go back and clean each hole. 
Hold the de-soldering tool ready, then heat the solder, 
quickly placing the de-soldering tool and triggering it as 
soon as the solder becomes liquid. This method destroys the 
chip being removed, but greatly reduces the chance of 
damaging an irreplaceable circuit board. The de-soldering 
tools listed can be used to remove a chip without cutting in 
much the same way, just be CERTAIN that all solder is 
removed before pulling the chip out. It is best to practice on 
an old circuit board before trying this on anything else. Chips 
are cheap, and usually suspected bad before removal. The 
exception might be when replacing the 6809 with a 6309. 
The 6309 (or another 6809) is replaceable, the CoCo moth- 
erboard is not! 

5) The only way to learn to solder is by practice! Get an old 
circuit board and practice soldering wires and chips to it. 
Remove some ICs also, destructively first, then try remov- 
ing without damaging the chip or circuit board. You'll be a 
decent solderer in no time! 

6) Always, ALWAYS, replace a bad chip with a socket! 

Sockets only cost a few cents (only $1 for a 40 pin), and if 
the repair has to be repeated it will be much easier. Using 
sockets also reduces the possibility of heat damage to the 
replacement IC. 

The "necessary" items could be purchased at the time of 
writing for under $40, with the optional items an additional 
amount under $20, plus another $20 for the logic probe. 
Almost any repair the average hobbyist is capable of making 
can be done with the "necessary" tool list, the "optional" list 
makes the job a bit easier, especially when working with ICs 

Solder wick is NOT recommended for the novice. The 
vacuum type solder removers are more efficient and easier 
to use. If one is practiced and comfortable with wick, by all 

General Troubleshooting 

Let's start with checks at the major chips. These checks will 
indicate a lot of potential problems. Problems aren't neces- 
sarily the same in all cases, so check the suspected chip as 
well as any others in the same circuit. It is possible that 
conditions other than those shown could cause the same 
results listed. A short description of the major components 
and common problems follows troubleshooting tips. 

The following charts list logic probe readings (computer 
turned on) of the major ICs. A VOM will read highs as +5 V, 

Tandy's Little Wonder 

page 89 

lows as OV. A pulse should read as a bouncing or wavering 
reading between OV and +5 V. Low/pulse will read OV, high/ 
pulse +5V. A VOM is not very accurate when reading 
anything other than a steady high or low signal. 









2 NMI 






3 IRQ 












7 Vcc 






8-11 A0-A3 






12 A4 






13 A5 






14-18 A6-A10 






19-20 A11-A12 






21 A13 






22 A14 


16-19 A0-A3 



23 A15 






24-31 D0-D7 






32 R/W 






34 E 


23-24 A6-A7 



35 Q 












40 HALT 







1 MA0-MA3 n/a 



1 MA4-MA5 n/a 



MA6-MA7 n/a 


































NOTE: 6809 address signals will read +2.4-4. OV and clock signals +2.4V on a 
VOM. HALT will also read +5 V. 

PIAs (6821, 6822) 

VDG (6847) 










1 GND 





2 PAO 





3 PAl 





10 DD7 





4-9 PA2-PA7 

low high 




10 PBO 

low h/p 




11 PBl 

n/c li/p 




12-17 PB2-PB7 

high li/p 




18 CBl 

high h/1 


Y (low 

comp. video) 

19 CB2 


29-30 GMl-GMO low 

20 Vcc 





21 R/W 





22 CSO 





23 CS2 

high h/p 




24 CSl 










26-33 D7-D0 







35-36 RS1-RS2 


37-38 IRQB-IRQA high h/p 

39 CA2 


40 CAl 

high h/p 

h/p = high or pulse, 1/p = low or pulse, h/1 = high or low 
h/p/1 = high, pulse, or low 

NOTE: Pin 28 (Y) of the VDG is a source for a weak (about 
IV peak to peak) monochrome composite video signal. The 
color composite signal is available at pin 1 of the RF 
modulator or pin 12 (unamplified) of the video mixer 


If testing of the listed signal gives results other than those 
shown, the tested chip or part of the circuit attached at that 
point is faulty. Check all leads before replacing a chip. 

Other chips, even those in peripherals, can be easily tested 
also. Take a good working computer, disconnect all periph- 
erals (except a TV... don't use a monitor, interference won't 
show the same!), and test each chip with a logic probe or 
VOM. Note any interference on the TV display. While not 
the most accurate testing method, TV interference (or lack 
thereof) will indicate potential problems. Make a testing 
chart for each chip. Another working computer of the same 
model should give the same results. 

Many of the 6809 signals can also be checked at the car- 
tridge port, so check there also, especially if the problem 
appears to be a peripheral that connects to the port. Just 
because a signal is present at the CPU doesn't mean it is 
reaching the port, or any peripheral plugged in there. If a MPI 
is being used, check each port for the same signals. The 
following tips should be checked with power ON unless 
otherwise indicated. 

1. If computer is running but experiencing intermittent 
problems or problems in just one area, run a diagnostic 
program and test the area believed to be at fault. If all checks 
good, run complete test cycle. 

2. Unplug ALL devices (except TV or monitor) and see if 
computer works correctly first. If it does, plug each periph- 
eral back in one at a time, checking operation after each. 
Repair/replace faulty peripheral. 

3. No or higher/lower than +5V on Vcc - check power 
supply. Also checkbypass capacitorbetween Vcc and ground. 

4. No clock signal - check for signal at SAM (pins 13 & 14) 
or GIME (pins 6 & 7) outputs. If nothing, check at crystal 
inputs (SAM pins 5 & 6, GIME 2 & 3). Touching a logic 
probe to either of these pins will produce a good bit of TV 
interference (TV only, not monitor), indicating the crystal is 
working. If still no signal, check capacitor and resistor in 
clock circuit. If they are good, replace crystal. If the crystal 
& circuit are good, replace SAM or GIME. If a signal is at 
the SAM/GIME outputs, check traces between there and 

5. With power OFF, check address and data lines for conti- 
nuity first (VOM + on one end, - on the other end of the trace 
or a section of). Then check for resistance between trace and 
ground. All should be very near the same. If not, look the 

page 90 

Tandy's Little Wonder 

circuit over and see if there is a reason for the difference. If 
none found, there could be a possible short between that 
trace and ground. Check resistance from one trace to an- 
other. There should be a high resistance. If not, suspect a 
short between traces with low resistance (check each line 
with all the others). Run diagnostics for further checks. 

6. If ground is high, replace chip (internal short). If no low 
logic probe on ground, chip should be replaced. 

7. The address lines of the SAM/GIME (A0-A15) should 
indicate an address in the BASIC ROM. Check each with a 
logic probe. A pulse only or pulse/low indicate a low (0), 
pulse/high a high (1). The combination should indicate a 
binary number (10100111110100000 in early CoCo 1 
[A7D0]) which is a location in the BASIC ROM. Convert to 
hex or decimal and check the memory map for location. If it 
isn't in BASIC ROM, there is a problem between the CPU 
and SAM/GIME. 

8. If the pattern on SAM pins 25-27 (GIME 29-3 1) are other 
than indicated, replace the SAM/GIME. The pattern shown 
selects the BASIC ROM. 

9. If SAM pins 28-35 and pins 11 & 12 are other than shown, 
replace the SAM. These are used by the multiplexer. 

10. SAM pins 9 & 10 are frequency driven. Check by 
presence of a logic pulse and interference on a TV screen. 
SAM pin 7 must also show a pulse. If these tests fail, replace 
the SAM. Test only pin 10 of the GIME. 

1 1 . If any but the data pins on a PIA read differently than 
noted, suspect a bad PIA. The PIA may not be initialized 
properly though, which indicates a problem in the CPU or 
ROM circuits, SAM, 74LS138 3/8 decoder, or GIME. 
Check these before replacing the PIA. 

12. If there is a signal other than a pulse on the data lines of 
a PIA, the trouble is somewhere along the data bus, not in the 

13. Any of the signals coming into the VDG could be bad, 
producing bad output. Check the inputs first. If they are all 
correct, check outputs. Bad outputs require replacement of 
the VDG. If inputs are bad, check circuitry going into them. 

The previously listed tips are just that- tips, not complete 
trouble shooting procedures. They should be enough to get 
a repair started on the right track. Unless the repairer has a 
lot of patience and trouble shooting experience, repairs are 
usually limited to replacing one of the major chips. These 
chips provide so many functions of the CoCo that one of 
them usually is the problem (more often than not the CPU). 

MC6809 CPU 

(also HD6309 in emulation mode) 

The CPU usually needs replacing when garbage is displayed 
on the screen, especially vertical columns and ampersands 
("@" signs). Other, random garbage could be caused by other 
components, though the CPU is still suspect. Most totally 
"dead" CoCos are due to a blown 6809. There are no buffers 
between the 6809 and the cartridge port. Pin 9 on all CoCos 
has +5V (300mA) on it. The original CoCo also has +12V 
(300mA) on pin 2 and -12V (100mA) on pin 1. Anything 
removed or inserted from the cartridge port at a slight angle 
while the computer is on can blow the processor by crossing 
one of these powered pin with an adjacent pin. This would 
apply power to the Q clock (pin 7), data bit 1 (pin 11), HALT 
(pin 3), or NMI (pin 4) pin of the 6809. Later ROM Paks and 
cartridge peripherals have a shorter land on pin 9, reducing 
the likelihood of a short, but not eliminating it. 

Before replacing the 6809, make sure no peripherals are 
plugged in and test the computer again. A bad disk controller 
or joystick can cause the computer to lock up or appear dead. 
Clean the GIME in a CoCo 3 and check the SAM in a CoCo 
1/2 before replacing the CPU. Check all other possibilities 

MC6821/MC6822 PIA (all models)Keyboard, Cassette, 
Serial Port, Joystick, Sound, & Video 

All Color Computers use two PIAs (Peripheral Interface 
Adapters), one for the keyboard and one for cassette, serial, 
and joystick I/O as well as sound and video outputs. The 
CoCo 3 uses a customized PIA (LSC81001) for keyboard 
input. It is unclear just what was changed in this chip, as a 
standard 6821 or 6822 will work just fine. The 6822 is a 
more robust version of the 6821- the 6822 will handle 
higher voltages without damage. It is suggested that a 6822 
be used in place of a blown 6821 for durability. No letter in 
the number indicates IMHz operation, an "A" 1.5MHz 
(68A22), and "B" 2MHz. A IMHz rated part will generally 
work at 2MHz, it just isn't guaranteed by the manufacturer. 

A keyboard problem could indicate a bad address line on the 
keyboard PIA (closest to power supply). It could also indi- 
cate a bad trace on the mylar ribbon "cable". Pull the mylar 
strip out of its socket with a firm tug. It isn't as delicate as it 
looks- pull it out! Now would be a good time to spray a bit of 
cleaner in the socket. Check continuity of the traces with a 
VOM. Bend the mylar strip as it is being checked- the break 
may be small and only show when the strip is flexed. If one 
is found to be bad, look carefully for the break. A break can 
be fixed with a rear window defogger grid repair kit (such as 
Loctite #15067), usually available in auto parts stores. 

The other PIA, a 6821, is used for cassette, joystick, and 
video I/O (video in CoCo 1/2 only). Check it if experiencing 
problems in these areas, especially if an input device has 
been used in the joystick port other than a joystick (video 
digitizer, temperature sensor, home built project, etc.). 

Tandy's Little Wonder 

page 91 

MC6883 and 74LS783/785 SAM Chip (CoCol/2) 
SAM stands for "Synchronous Address Multiplexer". This 
chip replaces a good deal of circuitry normally required for 
output from the CPU. 

The main job of the SAM (MC6883 or 74LS783 in early 
models, 74LS785 in later CoCo 2s) is to produce the various 
clock frequencies required by the CPU and video. A few 
capacitors, resistors, and a 14.3 1818MHz crystal make up 
the master clock frequency. The SAM divides this value by 
four to generate the RF color video frequency of 
3.579554MHz. The CPU "E" and "Q" frequencies, which 
must be 90 degrees out of phase with each other (a job also 
handled by the SAM), are created by dividing the master 
clock by 16. Any change in the master clock affects both 
signals. Anything other than the above video frequency 
renders the video output useless, which is why the crystal 
can't be changed to speed the computer up. The CPU fre- 
quency is altered by the speed up poke, which reduces the 
divide value to eight. 14.31818 divided by 16 = 
0.8948862MHz, by 8 = 1.7897725MHz... just under 1 or 2 
MHz. This was necessary to produce the required video 
signal, which must be exact (the CPU signal can vary a good 
deal from the rated speed). 

The second job of the SAM is device selection. The portion 
of computer circuitry looked at by the CPU is controlled 
through the address lines of the CPU. Internal registers of 
the SAM can be addressed or up to eight external devices can 
be addressed. For external device selection, the SAM has 
three chip select lines which are connected to a three to eight 
decoder chip. Devices are selected by a combination of "on" 
and "off settings of the three select lines (there are only 
eight possible combinations). 

The final job of the SAM is address multiplexing. In sum- 
mary, this means that the address and video signals are used 
in different combinations to form a larger number of ad- 
dresses than otherwise possible. These addresses activate 
different portions of RAM. 

There are only two versions of the SAM. The MC6883 and 
74LS783 are the same except for designation. A slightly 
improved version, the 74LS785, was introduced in late 
Korean made "A" model CoCo 2s and is in all Korean "B" 
models. The '785 will replace the MC6883 and 783, but a 
'783/MC6883 WILL NOT fiinction in place of a 785. 

It is hard to pin point particular problems that could be 
caused by the SAM because this chip is the "lungs" of the 
system (if the CPU is considered the heart). The SAM 
affects total operation of the computer. Commence with 
eliminating all other possible problems then proceed to the 
checks outlined under "General Troubleshooting". If the 
problems start only after the computer has been on a while, 
add a heat sink as described in the previous paragraph before 
replacing the SAM. 

MC6847 and MC6847T1 or XC80652P VDG 

The 6847T1 (or XC80652P) is an enhanced version of the 
original 6847. In order to make it perfectly software com- 
patible with the older 6847, the enhancements aren't readily 
accessible. This chip is used in all CoCo 2s with a "B" in the 
catalog number. It cannot be used as a direct replacement for 
the older 6847 as the pin assignments are slightly different. 
To use the Tl in an older CoCo, one chip has to be removed 
and some re -wiring done. This was described in the October 
1986 issue of Rainbow ("More on the Video Display Gen- 
erator", pp. 88-92). 

The most important change was true lower case on the 32 
column screen, something Tandy chose not to support for 
backwards compatibility purposes. This mode can be tempo- 
rarily invoked by typing POKE &HFF22, (PEEK(&HF22)or 
16). To enable lower case mode all the time, bend VDG pin 
30 up and solder a wire from it to pin VDG pin 1. An SPDT 
switch may be used to make the change temporary. Bend pin 
30 up and wire to the center pole of the switch. Solder a wire 
from pin 1 to one of the other switch poles, from the other 
pole to the socket hole (or cut leg) of pin 30. 

The second change involves the screen border. Normal text 
mode is black letters on a green screen with a black border. 
The border can be changed to green by typing POKE &HFF22, 
(PEEK(&HFF22 or 64). Change to lowercase AND green 
border with POKE &HFF22, (PEEK(&HFF22 or 80). The 
green border can be made permanent by bending pin 27 up 
and soldering a wire to pin 17 or wiring a switch exactly as 
for lowercase only, substituting pin 27 for pin 30. 

The third change provided inverse video (a black screen with 
green characters). POKE &HFF22, (PEEK(&HFF22 or 32) 
invokes this mode, with POKE &HFF22, (PEEK(&HFF22 
or 48) invoking inverse and lowercase. This can also be made 
permanent by wiring pin 29 the same as pin 27 and 30. 

The SAM runs quite a bit hotter than most of the other chips. 
Over heating can cause failure and intermittent problems. 
Many users stuck heat sinks (a pair of TO-220 types, #276- 
1363, or similar longer type) on top of the SAM with heat 
sink grease (#276-1372). This will definitely increase the 
life of the SAM, especially if the computer is on for long 
hours or in a particularly warm environment. 

WARNING: Hardwiring these modes (jumper to pin 17) 
will result in the loss of some graphics modes! A "no switch" 
modification using a 74LS157 to automatically switch be- 
tween text and graphics modes was described in the Decem- 
ber 1986 Rainbow ("The No Switch VDG", pp. 98-101). 

After 30 minutes or more of operation, intermittent video 
problems (random characters in the second and ninth col- 
umns) would start occurring on early models of the CoCo 1 . 

page 92 

Tandy's Little Wonder 

A short time after the video problems started, the computer 
would lock up. Because the SAM gets hot, it was initially 
thought to be the problem. Tandy issued two fixes. The first 
fix didn't do thejob, so a "Final Fix" (that's what Tandy called 
it!) was issued. This consisted of a small, T'x 1.5" circuit 
board with a logic gate and binary counter on it (plus a couple 
resistors and a capacitor). These components formed a pulse 
generator that cleaned up the horizontal synchronization 
(HS) pulse coming from the VDG. The pulse would become 
unstable as the VDG warmed up. The Tandy fix restricted the 
HS pulse to four clock cycles, synchronized to the falling 
edge of the E clock. The original pulse was 4.5 cycles long. 

The Tandy "Final Fix" kit has long since been discontinued. 
If a CoCo 1 is found without this kit installed, it can still be 
used reliably. The culprit is indeed heat, but in the VDG. 
Mounting a heat sink (pair of #276-1363s) with heat sink 
grease (#276-1372) to the top of the VDG will probably 
cure the problem. If not, further work to remove heat from 
the case is necessary. See "Power Supply Repairs" for some 
suggestions. Cooling the SAM can also help (same as cool- 
ing the VDG). 

There was a problem with the original (1986) GIME chip. 
Subtle timing differences between the CoCo 1/2 and CoCo 
3 created "sparklies" on some monitor screens, caused 
intermittent problems with hardware that plugged into the 
cartridge port, and created a "bootlist order bug" (BLOB) 
problem with OS-9. This can be corrected by either replac- 
ing the GIME with a newer one (1987 manufacture) or 
changing the timing signal on the motherboard. The timing 
problem affects the ROM selection circuitry and the CTS 
and SCS lines of the cartridge connector. 

The motherboard modification requires adding an extra gate 
so that the ROMs are only read during the "E" clock portion 
of the read cycle. This does require basic electronics skill, 
but isn't overly hard to do. 

1) Mount a 74LS02 Quad NOR gate somewhere near IC9 
(74LS138) and supply power to pin 14, ground pin 7. 
HINT : Mount the 74LS02 "piggy back" on another nearby 1 4 
pinchip. Bend all legs straight out except pins 7 and 14. 
Solder the two unbent pins to pins 7 and 14 of the board 
mounted chip, supplying power and ground to the 74LS02. 

The GIME (CoCo 3) 

The GIME (Graphics Interrupt Memory Enhancement) re- 
places the SAM and VDG (see) in the CoCo 1/2 and also 
handles the enhanced graphics and memory capabilities as 
well as interrupts of the CoCo 3. The GIME is suspect of 
causing problems in several instances including: 

Screen flicker or "sparklies" 

Intermittent "trash" on the screen 

Intermittent memory loss 

"Missing" characters (screen shifted 1-2 characters to the 


No horizontal synchronization signal at power up 

Most of these problems can be cleared by cleaning the 
GIME and socket. Use a pair of small screwdrivers to 
carefully pry the GIME out of it's socket from the comers. 
Note how the GIME is oriented in the socket! It can be easily 
rotated and may be damaged if inserted wrong (lettering is 
usually right side up with lettering on the 6821 PIAs and the 
68B09). Once out, clean the contacts on the chip with a 
pencil eraser or alcohol. The socket should be cleaned with 
alcohol also. It is best to use a foam swab, not cotton. Tuner 
or electronic contact cleaner in a spray can may also be used. 

If cleaning the socket doesn't solve the video problems, 
replace C64 (a 150pf capacitor) with a 220pf, 50V (or 
greater), 5% tolerance ceramic disc capacitor. This capaci- 
tor is in the clock circuit and may cause the clock to power 
up into an abnormal state. These problems are most likely to 
occur when the computer is cold and may be less noticeable 
after warm-up. 

2) Solder ajumper wire between pins 14, 13, 12, 10, 9, 2, and 
3; disabling three of the four NOR gates (inputs tied high). 

3) Solder a wire between pin 3 of IC9 to pin 5 or 6 of the 
74LS02 (GIME line S2). Solder a wire from the other pin (5 
or 6) to the intersection of R9 and CIO ("E" clock signal 
from the GIME). 

4) Cut pin 4 or 5 (not both!) of IC9 as near the circuit board 
as possible. Bend the remaining portion out and solder a 
short wire to it. Solder the other end to pin 4 of the 74LS02. 

Unless intermittent hardware problems or "sparklies" on the 
screen appear regularly, this modification is unnecessary. It 
should not be required with 1987 and later GIME chips as the 
problem was addressed inside the GIME. 

Disk Controller and Drive Repairs 

The first step in repairing a disk controller is to make sure 
the controller is the problem: 

1 . Unplug the controller and make sure the computer oper- 
ates normally. 

2. A faulty disk drive or cable could also cause problems. 
Test the suspected controller, cable, and drives on another 
system if possible. Check the cable for continuity. 

3. If another, known good disk system is available, see if it 
works correctly on the problem computer. 

4. A software problem could be the culprit. Make sure a cold 
start is effected if a problem occurs after running a m/1 
program. Turn the computer off for a few seconds, then back 

Tandy's Little Wonder 

page 93 

on. CTRL-ALT-RESET may not clear everything up on a 
CoCo 3- turn it off to be certain! 

5. Check all the cartridge port lines using the logic probe 
readings for the 6809 previously listed. The CPU could be 
at fauh. 

Note that the 12V controller requires an MPI (for +12V 
power) if used with a CoCo 2 or 3. +12V may have been run 
to the controller from the disk drive power supply by an 
enterprising user; such was common when the CoCo 2 first 
came out. This type setup may be used on a CoCo 3 also. 
Problems will occur when running a 12V controller with 
OS-9 Level II, and possibly under DECB if running the CPU 
at double speed (OS-9 Level II runs at double speed all the 
time). This is due to the design of the 12V controller and 
cannot be fixed. 

If the disk controller is still suspect, clean the contacts on 
each end of the controller The case will have to be snapped 
apart to properly clean the contacts. On long (approx. 6") 
controllers, a single phillips head screw is located under the 
label on top. On short controllers (approx. 4"), the screw is 
located under a seal that reads "WARRANTY VOID IF 
LABEL REMOVED" (or something similar). Remove the 
screw and snap the case halves apart. Clean the contacts with 
a pencil eraser until they are bright and shiny. Re-assemble 
and test the system. This cures most unexpected errors. 
Incidentally, any peripheral plugging into the cartridge port 
or MPI can be affected by slightly corroded (dirty) contacts. 
Clean in the manner noted. The sockets themselves can be 
cleaned by spraying with TV tuner cleaner or degreaser/ 
cleaner (see tool list). 

If the normal Disk Extended BASIC copyright notice ap- 
pears on screen but reading and writing to the disk fails (the 
drive light comes on andheads move. .. a"buzzing" soundcan 
be heard from the drives), one of three chips need to be 
replaced. The most likely culprit is the 7416 (or 7406) on 
the NMI and HALT lines, especially if the controller is used 
in a CoCo 1 or MPI. These pins are the second from the left 
(looking "in" at the cartridge slot end of the controller board) 
on the top and bottom. Use the schematics to locate the 
correct chip, or replace both. Cut the offending chip out and 
replace with a socket. It is suggested that a 7416 be replaced 
with a 7406, which will withstand higher voltages than the 
7416. Note that there are two 7416s. The second likely 
culprit is the 74LS221, which is the second most likely to 
blow chip. On the 12V controllers, the 74LS02 and 74LS04 
have a nasty habit of blowing. If the 7416 in the NMI and 
HALT hues is blown, the 6809 and SAM should also be 
checked, as they usually go down with a +12V short in a 
CoCo 1 or MPI also. 

If replacing these three (two 7416/7406, one 74LS221) 
doesn't do the trick, suspect the main disk controller chip 

or auxiliary disk controller chip (WD9216, not used on 
WD1773 models). On 12V controllers (those with the 
WD 1795) also suspect the WD 1691 and WD2143. Unfor- 
tunately, these disk controller chips are ALL hard to come 
by, as they are no longer manufactured. They may still be 
found in large parts warehouses, however. The ROM could 
be at fault, but rarely gives any problems. 

If the problem is determined to be a disk drive unit, replace 
it with another drive. Floppy drives, especially the 360K, 
5.25", double sided units used with the CoCo are not eco- 
nomical to repair. A simple alignment would cost more than 
a used replacement drive. Remember that standard 360K 
IBM type drives work with the CoCo and will read/write 35 
track single sided disks. This is the perfect time to upgrade 
those single sided drives... see the "Upgrades" section. 

A less common problem is a worn cartridge port connector 
on the motherboard. This can be identified as the problem 
when VERY mild wiggling or tilting of the controller causes 
the system to crash or give intermittent results. If this 
occurs, clean the controller and connector first. If this 
doesn't solve the problem, the connector must be replaced. 
First remove the mother board then the ground plane (foil 
covered cardboard backing, held in place with push-in clips). 
Then clip each leg on the connector close to the connector 
housing. Remove each wire individually by heating with a 
soldering iron and pulling out with needle nose pliers. 
Carefully clean all holes with a solder sucker. Put a new 
connector in position and solder it in. Connectors can be 
purchased from Tandy National Parts. 

RS-232 Pak Repairs 

There are a few common repairs for the Tandy RS-232 Pak. 
Note that most other RS-232 adapters are similar in design, 
meaning these tips may be used for them also. 

A dead RS-232 Pak usually has one or two blown chips- the 
RS-232 level converters. These are the 1488 and 1489 
chips. Check each line while sending data over the RS-232 
port with a terminal program or diagnostic utility. Replace 
the chip that supports the lines not receiving signals. These 
are really cheap chips (each chip and socket under $ 1 .00) so 
don't hesitate to cut them out and replace with sockets if they 
are suspect. Tests can be conducted at the inputs and outputs 
of the chip also, making sure they follow each other. 

Next check the AZTEC voltage converter. This chip converts 
+5V to the RS-232 standard +12V (1) and -12V (0). Check 
for+12Vonpin5 and -12V on pin 3 of the converter, +12V 
on pin 14 of the 1488 and pin 10 of the 1489 (on other side 
of resistor R2), and -12V on pin 1 of the 1488. Don't forget 
to check the traces and all components between the con- 
verter and 1488/1489 chips (the 33mf capacitors near the 
converter and lOK ohm R2). 

page 94 

Tandy's Little Wonder 

Abad 6551 ACIA is possible, but rare, as the level converters 
receive voltage spikes or surges coming in from the source 
first. If replacing the converters fails to cure the problem, 
the 6551 may be suspect. It is easiest to check by replacing 
with a known good unit. Many Tandy and aftermarket paks 
have a socketed 6551, but some later Tandy units don't. 
There have been some reports of intermittent failure of the 
RS-232 Pak under OS-9 Level II. If this occurs, test the 
suspect pak under a DECB program. If it works fine then, 
replace the 6551 with a 2MHz rated 6551 A. Note that most 
6551 chips work fine at 2MHz with no problems. The 
majority of non-Tandy RS-232 paks use the 6551 A. 

In rare cases, the crystal may be damaged. If the pak initial- 
izes (DTR and RTS line change status when a terminal 
program is run) but no data is sent or received suspect the 
crystal. First check for continuity of the traces between the 
6551 and 1488/1489 and between them and the DB-25 
connector. If all is well, replace the 1. 8432MHz crystal. 

Multi-Pak Interface (MPI) Repairs 

If intermittent program problems are occurring with an MPI 
connected to a CoCo 3, check to see if the MPI has been 
upgraded. The 26-3024 MPI (large, gray or white case) 
requires a new PAL. The upgraded Tandy PAL will have NOT 
have a Tandy number on it. The four digit date code should be 
after 1 986. The original MPI PAL DOES have "Tandy" and a 
part number (8075144 for the later model). The small (26- 
3124) MPI requires a satellite board. The board and neces- 
sary wiring should be visible through one of the slots or 
cooling vents. See Upgrades for details. 

If some slots work and others do not, the problem is most 
likely in the SCS, CTS, and/or CART select circuitry. In the 
26-3 124 MPI (newest, small one), the big custom IC handles 
slot selection. In the large MPIs, slot selection is handled by 
the LS139 (SCS & CTS), LS153 (CART), LS368 (CTS & 
SCS), and LS374 (CTS, SCS, & CART) chips. 

Check to see if the slot selection problem is limited to the 
CTS and CART lines or only the SCS hne, or if both groups 
of switchable lines are affected. This may help narrow down 
the problem to a particular chip. 

The big custom IC in the new MPI is unavailable, and 
replacing it with small scale logic chips would mean making 
up a five chip circuit, or designing a complex PAL chip. 
There is a fuse map posted on Delphi in the CoCo SIG (also 
available from FARNA Systems) for burning 14L4 and 
16V8 PALs and GALs for replacement of that custom IC for 
anyone with access to a PAL programer. On the old MPI, all 
the chips are widely available small scale logic chips, except 
for the factory upgrade PAL chip. Information on program- 
ming this PAL is also on Delphi. 

It is easy to check the switching of the SCS line with a logic 
probe. Just put the probe on the line in a given slot, select that 

slot, and then try to WRITE a value to the appropriate address 
range in the SCS line, and see if the probe flashes. Check the 
CTS line by plugging a ROM Pak into the slot to be checked. 
If the Pak comes up on screen, then the CTS line is good. 

Intermittent problems after the MPI has been on for a while 
usually occur because of a bad buffer IC. There are four 
74LS367 (control functions and address bus) and one 
74LS245 (data bus) buffers. To find out which is the culprit, 
remove the upper case of the MPI, then plug back into the 
computer and commence operations. When the computer 
locks up, determine which chip is warmest. One method is to 
turn the computer and MPI off, then unplug the MPI and 
physically touch each chip. One should be warmer to the 
touch than the others, maybe even hot. A better method is to 
spray each chip (being careful not to get much overspray on 
nearby chips) with "component cooler" (#64-3321). The 
computer should reset itself and/or resume operation as 
soon as the offending buffer is cooled down. Replace the 
defective chip. 

If an individual slot is causing problems the connector or 
cold solder joints could be the problem. Inspect the connec- 
tor first, making sure all contacts are visible and protruding 
enough to connect with a circuit board. Next try cleaning the 
socket with tuner cleaner or cleaner/degreaser. Clean the 
device being inserted into the suspect slot also. Check the 
solder joints on the underside of the board. If some of the 
joints appear dull, re-melt the solder with an iron. Test the 
unit to see if the problem persists after each check if a 
problem is found. If the connector needs to be replaced, 
order a new one from Tandy National Parts. This connector 
cannot be destructively removed- proceed with removal 
with extreme caution if not experienced with a de-soldering 
tool ! DO NOT attempt removal with solder wick. Irreparable 
damage to the circuit board will result. Go through the 
checks for slot selection circuitry before determining if a 
connector is bad. Also, try different devices in the suspect 
connector, there could be a device problem. 

Finally, if the entire MPI is dead, suspect the power supply. 
See the next section for repair details. 

Power Supply Repairs 

The power supply in all CoCo models, MPIs, and disk drives 
are pretty simple and easy to repair. Remember that live 
llOV AC current is at the transformer, so be extremely 
careful when attempting repairs, especially if the computer 
is still plugged in for testing. 

On older D board CoCo Is, loss of +5V power is usually 
caused by the 6.2V zener diode. This diode will fuse if 
overloading occurs, sacrificing itself (and grounding +5V 
power out) to save the rest of the power supply. Check the 
zener diode with power off Current should only pass through 
any diode in one direction only. If it passes from both ends, 
the diode is fused and will need to be replaced. On the D and 

Tandy's Little Wonder 

page 95 

E board CoCo, the zener is a 1N4735 (CR17). Another 
popular reason for loss of +5V is a burned out .33 ohm, 2 
watt power resistor (R66). 

The CoCo 2 uses a custom Tandy IC for much of the 
regulator circuitry. This chip, the Supply And Level Transla- 
tor (SALT), handles +5V power regulation, RS-232 level 
translation, and cassette input. This chip is (was?) only 
available from Tandy. Early CoCo 2s used a SALT that 
required 3.9V zener diodes on the incoming RS-232 lines 
for protection. Later model CoCo 2s used a newer SALT that 
was internally protected. The later SALT can be substituted 
for the early and vice-versa. Just either eliminate or add the 
protective 3.9V zeners. The zeners are located near the 
power supply (CR5 and CR6). 

A problem common to all CoCo and MPI power supplies is 
cold solder joints. The joints expand and contract with 
heating and cooling. When they expand, intermittent loss of 
power can result due to cracks in the joint. This usually 
occurs after the computer has been on a while, progressively 
getting worse. A cold joint won't be as shiny as a good one, 
so might be visible under close scrutiny. The cure is to re- 
melt the solder at the joint. 

Heat can also cause problems. Most of the heat generated in 
a CoCo 1 or 2 is from the large TO-3 cased power transistor. 
It is hard to miss- large, round, and in a heat sink. There are 
many cures for this, ranging from replacing the power supply 
as described in the next paragraph to installing a fan. Some 
users merely added vents directly over the power transistor 
by drilling holes in the case. Others just used a small desktop 
fan blowing over the computer. Larger heat sinks were also 
used. I have even seen the transformer removed from the 
case via longer wires to the motherboard! The CoCo 3 power 
supply is less likely to cause heat related problems. 

The old style +5V power supply is somewhat complicated 
and runs a bit hot. With a basic knowledge of power supply 
circuitry and a schematic of the board, the old power supply 
can be replaced with a TO-3 case 7805 1.5A monolithic 
regulator, which can be mounted in the socket and heat sink 
of the TO-3 case power transistor. Study a schematic to 
locate where traces must be cut or jumpered. Add 2.2mfd 
tantalum capacitors on the input and output lines of the 7805 
to prevent oscillation. MPIs have a similar power supply. 

Another method of power supply replacement is to use a PC 
style or other surplus external power supply. Mounting the 
power supply can be as elaborate as re-packaging the CoCo 
in a PC style (or other) case or simply making cables long 
enough to mount the supply outside the CoCo case (on the 
floor under a desk, beside the CoCo, etc.). Any good +5V 
power supply will work for a CoCo 2 or 3. The CoCo 1 
requires -5V, +12V, and -12V (some of the older chips 
require the negative voltages to operate). If using a MPI, 
remove that power supply also and run both the CoCo and 

MPI off of the same external power source. If a heavy 
enough supply is used (such as a PC type) disk drives can be 
powered from the same also. Use some type of connector 
between the CoCo, MPI, and power supply to facilitate easy 
removal. An external power supply gets rid of a lot of heat in 
the CoCo case by removing the transformer, regulators, and 
power transistor. 

There are several ways to connect an external power supply, 
depending on which CoCo is being connected: 

CoCo 1: Cut the traces on the circuit board on the CoCo 
power supply side of test points (TP) 9, 10, 11, and 1 2 (D & 
E board, possibly the same number for others) between the 
last capacitor and the power supply. If this is a tantalum 
capacitor, replace with a 50-lOOmfd ceramic disc type for 
filtering. DO NOT leave a tantalum capacitor in the circuit! 
These points were provided for testing the power output of 
the three regulators. The 78M12 (U17, TP 9) provides 
+12V, 79M12 (U18, TP 10) -12V, 79L05 (U19, TP 1 1), and 
the 723C +5V (U13, TP 12). The NC board eliminates the 
79L05 and provides unregulated -5V at C82. Apply the 
corresponding voltages from the external power source. 

CoCo 2: Feed pins 15 and 16 of the SALT (SC77527 in all... 
ICl in original CoCo 2, IC7 in Korean [A & B] models) with 
-12V and +12V, respectively. WARNING: Connecting in 
reverse order could damage the SALT chip and other com- 
ponents. Cut traces and feed +5V as follows: 

26-313X - Cut trace between C5 and CI 1 and C6 and Cll. 
Supply +5V on positive side of Cll. 

26-313xA or B - Cut trace between C34 and C35. Add +5V 
on positive side of C34. 

Replace Cll and C34, respectively, with 50-lOOmfd ce- 
ramic disc capacitors to provide some filtering on the +5V 
input. DO NOT leave the original tantalum capacitors (Cll 
& C34) in the circuit! 

CoCo 3: Feed +12V and -12V to the SALT (IC8) as for the 
CoCo 2. Cut the trace between C14 and R19, applying +5V 
to the positive side of C14. Cut the trace between C30 and 
C3 1, applying -12V to the positive side of C30. Next cut the 
trace between Ql and C29 (cut the main trace between the 
leg that goes to C29 and that goes to SALT pin 16). Apply 
+12V to the trace that goes between pin 16 of the SALT and 
the input of Q 1 . 

C29, ,, 


+12V ™ 

CUT HERE ^ /C30 


page 96 

Tandy's Little Wonder 


PAL (European) CoCos: The PAL version of the CoCo 
follows the same procedures as outlined for the American/ 
Korean made units and CoCo 3. The only difference is that 
the PAL encoder (a satellite board near the modulator) 
requires +12V on one of the connectors (seven pin CN9 on 
the CoCo 3). The +12V input point is clearly marked on the 
encoder circuit board. Cut the trace on the motherboard 
going to the +12V pin and then supply the pin with +12V 
from the power supply. 

Note the voltages fed into certain points. These voltages are 
supplied by the normal CoCo power supply, and may be used 
for testing. 

Voltage/Amperage Requirements: 








CoCo 2 



CoCo 3 







Disk Drive 



Hard Drive 




Hoppy driveratingisforatypical 5.25" half height drive. The 
+12V current is with spindle motor and stepper running at 
the same time. In a two drive system, both spindles will be on 
at once, but only one stepper. + 12V at l.OA would therefore 
be sufficient Old full height drives require as much as 50% 
more power than listed. Full height drive cases have adequate 
power capacity to drive two half height drives or a half height 
floppy and hard drive. It should adequately power even two 
3.5" hard drives. The hard drive power requirements are for 
average 5.25" half height models. Older full height models 
will use more power, and newer 3.5" models much less. For 
the +12V line, 1.2A is drawn only on start-up, after which 
600mA is drawn to maintain speed. Most power supplies are 
rated at a steady load and will put out over their rating for 
short periods (hard drive start-up). Find the total wattage by 
multiplying each voltage by the required amperage, then 
adding all together. A CoCo 3 with two floppy drives would 
require a minimum of 30 watts (+5Vx2.6A=13W; 
+12Vxl.2A=14.4W; 13W+14.4W=27.4W, rounded up to 
30). Always allow at least 10% over the required capacity for 
items (such as the disk drive controller and RS-232 Pak) that 
aren't included in the calculations, since they draw very 
small amounts of power. 

Alternate Power Connection Method Rick Ulland 
The trace-cut methods previously described are the neatest 
way to add an external power supply and are recommended 
by Marty Goodman. There is an equally effective method for 
those unwilling or unable to cut traces. This method is 
described for a CoCo 3 and has been working reliably for a 
number of years. Review the schematics of other models to 
apply to them. All the components that require removal can 
simply be cut out on a CoCo 3. 

The CoCo Motherboard: 

1) Remove Ql (5V regulator on heat sink). 

2) CcHinect +12V to the unhanded end of D2 and D14. 

3) Connect -12V to the unhanded end of D4. 

4) Connect +5V to the end of R19 closest to Ql. 

5) Connect ground to the motherboard (one of the 
keyboard ground clip lands is a good spot). 
NOTE: "unhanded" end of diodes Dx is the cathode. 


1) Remove IC9 (front left side of board). 

2) Remove R7 (front right near slot switch). 

3) Connect +5V to circle labeled TPl (near slot 1). 

4) Connect +12V to circle labeled TP2 (near slot 2). 

5) Connect -12V to circle labeled TP3 (near slot 1). 

6) C(Minect ground to any ground point. 

7) Leave the power switch OFF position, or remove. 

8) Put slot selector to slot four. 

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Tandy's Little Wonder 

page 97 


miscellaneous items of interest to CoCo users.. 

The "Colour" Computer Down Under - Seigfred Remin 
The history of the Colour Computer in Austraha has been 
and continues to be a checkered one. The CoCo community 
here has seen the highs and lows reminiscent of a volatile 
stock on the worlds stock markets. 

Although Tandy introduced the Colour Computer to Austra- 
lia, it could be argued that it was given its real start in this 
country by Greg Wilson. Greg was instrumental in produc- 
ing the first magazine dedicated to the CoCo in Australia; 
The CoCo Magazine. Although it was heavily dependent on 
material from The Rainbow Magazine in its infant days, it 
quickly became an almost totally Australian content maga- 
zine. Greg also brought into Australia the first non-Tandy 
software from the USA, a move that Tandy was reluctant to 
make in the early years. 

The early to mid eighties could be recorded as the hey day of 
the CoCo in Australia. During this time a plethora of com- 
panies sprang into existence supporting what at the time was 
considered the ultimate home computer and a rival to the 
Commodore as a games machine. Also during this time a 
great number of user groups and CoCo clubs came into 
existence all over the country, some of these are still in 
existence today, years later. These user groups and CoCo 
clubs seemed to be made up of a different sort of computer 
enthusiast. Unlike those using other machines, the CoCoists 
seemed to genuinely want to help each other and were more 
interested in learning about the computer than pirating the 
latest software. That is not to say that an amount of pirating 
did not go on, to say other wise would be a travesty, but, 
compared to those clubs dedicated to the other machines, it 
was insignificant. 

Support for the colour computer in the eighties was phe- 
nomenal. There were the user groups and CoCo clubs. The 
CoCo Magazine, Softgold magazine. The Australian Rain- 
bow, The (American) Rainbow, Tandy, and hundreds of 
businesses ranging from chemists (drug stores in the USA) 
to dedicated computer stores Austraha wide. 

During this time a strong bond was forged between CoCoists 
not only in Australia but around the world. Letters and 
articles in the various publications ensured that contact was 
maintained between CoCoists in Australia, America, Europe 
and numerous other countries. It was not unusual to see a 
letter to the editor in an issue of Softgold asking for help 
with a particular problem from someone in New Zealand or 
even Holland. 

The advent of the CoCo 3 further advanced the CoCo com- 
munity in Ausfralia. At last there was a comparable memory 

on board without more expensive add ons, and the introduc- 
tion of OS-9 Level II put the CoCo ahead of the other, more 
expensive machines. OS-9 also saw a great number of 
programming gurus come forward and share their abilities 
with the community at large. The National OS-9 User 
Group in Brisbane, Queensland was formed, and is still 
going today. 

The mainstay of the CoCo community in Australia was The 
CoCo Magazine started by Greg Wilson and then taken 
over by Graham Morphett on Greg's untimely death. In the 
pages of this magazine was the contact needed by CoCoists 
from the vast outback of the country with those closer to the 
cities and the software and hardware vendors world wide. 
The magazine gave hope and a sense of belonging to those 
who were without telephones and received mail only once a 
month. Content included helpful hints, reviews of the latest 
soft and hard ware, and allowed users from the very young to 
the most experienced to share their programming abilities. 

Two things happened in the late eighties which almost saw 
the death of the CoCo in Australia. One was the loss of The 
CoCo Magazine produced by Graham Morphett and the 
second was the discontinuing of the CoCo by Tandy. These 
two events caused a large section of the CoCo community to 
move to other machines or to place their CoCos in the 
cupboard and forget about them for a while. It was also at this 
time that the majority of the businesses which had been 
supporting the CoCo decided to go to other machines or 
leave the computer business. 

Non-existent support resulting from these events left the 
remaining CoCo community in a very precarious position. 
They still used their CoCos and found more uses for them, 
but were slowly being forced to lean towards other machines 
as parts, software, hardware, and contact became scarce. 

It was at this time that Robbie Dalzell, a member of a CoCo 
club in South Australia, decided to do something about this 
state of affairs and began to produce a magazine called 
CoCo-Link. CoCo-Link again gave some support to the 
remaining CoCo community. It maintained contact, gave 
assistance to those still learning, and shared new found 
knowledge amongst those who subscribed. Robbie's maga- 
zine again kept the CoCo community together for a further 
period of four years. Notwithstanding the contact and sup- 
port provided by the CoCo-Link magazine, software and 
hardware still became increasingly harder to obtain. Those 
few who still carried products in Australia charged inflated 
prices which the community could not afford and those who 
were producing their own software had no way of marketing 
the products. 

page 98 

Tandy's Little Wonder 

When it seemed that the CoCo was again about to die a 
natural death, Fred Remin, a CoCo user, decided to ap- 
proach a number of companies in the USA with a view of 
obtaining software and hardware for the aihng CoCo com- 
munity in Australia. Success was slow but it was forthcom- 
ing with FARNA Systems, Rick's Enterprises, Sundog, 
Cer-Comp, and JWT Enterprises being some of the first 
to recognize an untapped market and responding to Freds' 
request. With software and hardware again being available a 
large number of ex CoCoists retrieved their CoCos from the 
cupboards and dusted them off to releam and once more 
enjoy the pleasures that come from using the CoCo. 

By the end of 1992 Robbie Dalzell had been producing the 
CoCo-Link magazine for four years and had decided that it 
was time for him to have a rest. CoCo-Link, however, has 
not ceased, it is now being produced by Fred Remin and is 
continuing to maintain contact between the CoCo users 
throughout Australia. 

In conclusion, the Colour Computer has in Australia had a 
checkered life span similar to its' evolution in other coun- 
tries. It has, however, maintained pace with its more expen- 
sive counterparts and continues to grow and surprise not 
only those who use it but also those who were under the 
impression that it was dead and gone or just a kids games 
machine. The advent of the Hitachi 63B09E coupled with the 
advances in both OS-9 and Disk BASIC will undoubtedly 
ensure that the CoCo will survive for many years to come. 
Australian CoCoists, like their American counterparts, have 
recognized the potential of the Colour Computer. While 
contact can be maintained and software and hardware is 
available, these users will ensure that this amazing computer 
system will outlive its strongest rivals. 

EDITOR'S NOTE: Anyone interested in obtaining CoCo- 
Link can contact Fred Remin at 1 1 Corcoran Cres, Canungra, 
QLD 4275, AUSTRALIA. His phone number is 011-61- 
754-3821. Please remember that Australia is 15 hours 
ahead of EST. Inquire about subscriptions. CoCo-Link is 
produced bi-monthly. Contact FARNA Systems about soft 
and hard ware from Australia. 

The "68xxx" Story - by Jim DeStafeno, former editor 
The idea to start a monthly publication centered around the 
revitalized OSK community that was brought on by the newly 
released OSK/KMA computers. The idea became more than 
a dream at the 1990 CoCoFest held in Atlanta Georgia 
sponsored by Dave Myers of CoCoPRO ! As I was told later, 
Fredrick Brown, manufacturer of the PT-68K2/4 com- 
puter boards; Ed Gresick, owner of Delmar Corp. and soon 
to become vendor of the System IV; Dan Farnsworth, 
author of REX-DOS and many application programs for it 
and SK*DOS; Jack Crenshaw and Ron Anderson, both 
nationally known writers of computer related books and 
magazine articles; and Gil Shattuck of Granite Computer 
Systems pulled two tables together at the hotel restaurant. 

After dinner the conversation turned to their perceived need 
for a magazine to unite the anticipated growth of the OSK 
community. After the 'fest I was contacted; told of the 
desire, and that Peter Stark, the author of SK*DOS, might 
be willing to lend a hand by giving me his magazine and a 
mailing list. It took a week to talk with people in the industry, 
line up a printer and get Randy Keippner to agree to do the 
layout. The 68xxx Machines was now in business. 

The aim was to satisfy the higher level user/programmer - 
quality not quantity. The idea was well received in the 
community. Despite our lack of experience the first issue 
was mailed Feb ' 9 1 , all of sixteen pages long. The format was 
small, 5 1/2" X 8 l/2"pages with small print. The result was 
full size information within a package that reduced produc- 
tion and mailing costs. 

By the end of the first year the subscriber base had grown m- 
a-n-y times over, and the number of advertisers had more 
than doubled. The number of pages was held at 24 to keep 
costs and quality under control. All bills had been paid on 
time since day one, including advertising in The Rainbow. 

It soon became apparent, however, that the traditional user 
base for OSK was not going to number into the thousands, 
not even one thousand. Trying to increase the number of 
potential subscribers, in addition to catering to the OSK 
user, several out of the main stream operating systems had 
been featured. Theses articles didn't increase the subscriber 
numbers very much. Requests to include OS-9 kept coming 
in. I had reasoned that since Rainbow hadn't done much with 
it, it wouldn't do a lot for 68xxx. But to leave no stone un- 
turned, I began to include one OS-9 article a month. 

Though we had made many changes by the June ' 92 issue, we 
were in a practiced groove and all was going well - we were 
continuing to get new subscribers and advertisers. Then, 
while working on the July issue, I received a copy of a new 
magazine called OS-9 Underground (0S9U). It was dedi- 
cated to OS-9 with a hint to lean toward OSK. In my opinion, 
it appeared to have a more professional flavor than 68xxx. 
I phoned the editor/publisher, Alan Sheltra. Among other 
things, he said such activities as authoring and publishing 
small periodicals was his profession. I told him that I thought 
there was not enough user/advertiser dollars to support two 
OSK/OS-9 magazines. With that point in mind we discussed 
combining the two publications. Previous to this discussion 
I had been trying to get the rights to publish the new OS-9 
Users Group magazine. When I received the news that Alan 
was going to do it I thought he might just as well do the whole 
thing. He and I went ahead with the merger/buy-out idea. 

As it turned out, the agreement was very simple. I would 
contribute my stock of OSK articles to 0S9U at no cost for 
a few months until Alan developed his own contacts in that 
world. The 0S9U action would be to take over the printing 
and mailing of the combined content magazine, under the 

Tandy's Little Wonder 

page 99 

mast head of 0S9U, to all current 68xxx subscribers. In 
exchange for this service, 68xxx would pay 0S9U for the 
print space its articles and ads used, as well as any extra 
mailing cost. To sweeten the deal, 0S9U would keep all 
proceeds from subscription renewals, new subscribers, and 
new advertisements. In exchange for the 68xxx no-cost 
mailing list, 0S9U would pay the postage cost of the OS-9 
part of the magazines sent to 68xxx subscribers. We both 
deemed it to be a fair exchange and the deal went through. 

To answer the question most often asked of me about 68xxx, 
all fifteen back issues are available at twelve dollars for the 
package, or one dollar per copy, not to exceed twelve 
dollars. Send payment to: Jim DeStafeno, RD#1 Box 375, 
Wyoming, DE 19934. 

EDITORS NOTE: Although The 68xxx Machines was 

dedicated to 68xxx based computers, this story is included 
here because many CoCo OS-9 users benefitted from the 
OS-9 articles. The OS-9 Underground was short lived, 
quietly disappearing after less than one years' existance. 
Jim DeStafeno is now the editor of MOTD (Message of the 
Day), the OS-9 Users Group publication, and president of 
the group. Jim got his start in OS-9 on a CoCo. 

Two Boys and a CoCo... Joseph Ahern and David McNally 

by Joseph Ahern, former editor 

It all began in the fifth grade when we were introduced to the 
Radio Shack Color Computer. Once a week our class was 
allowed to go to the computer room and use Color Logo. 
We soon learned how to master all those impossible shapes 
they had us draw. We had such a good time using these 
computers that both of us talked out parents into getting one. 

It was hard learning BASIC because up to now we had only 
used Color Logo. Both of us tried learning to program by 
spending hours reading through and typing the sample pro- 
grams from the Color BASIC manuals. After sharing each 
others' knowledge, we could do some simple programming. 
Within a years' time, Joe had saved enough money to buy a 
DMP-105 printer. This, along with a computer cassette 
recorder and a blank tape, was just enough equipment to 
make an attempt to start a small CoCo magazine. Shortly 
after, Joe came to school one day in June 1987 with the first 
issue of TRS-80 Computing. He said he had been working 
on it for a few weeks and asked me if I would like to continue 
with the venture. I loved the idea, so we teamedup and started 
working on improvements. 

That first issue looked like some natives had put it together! 
At the time we had no word processor and still a minimal 
knowledge of BASIC . Everything had to be printed using that 
nasty old PRINT#-2 statement. We even cut lettering from 
newspapers for the logo on the cover! 

Our first few customers were teachers at the junior high 
school we were attending. We had about four or five custom- 
ers for the longest time and printed monthly. After six 
consecutive months, it started to become time consuming 
and was interfering to much with our school work. Besides, 
it wasn't really worth the effort for just a few people. As a 
result, we stopped printing for a few months and figured that 
if we were to continue it would be published annually. 
However, with the purchase of many new development 
programs such as word processors and art programs, we 
figured that with some time, effort, and a lot of planning, we 
could re-start the magazine with a new format, bi-monthly 
frequency, and a raise in price. 

At this time we started promoting the magazine by using 
flyers. Our best customers were still our teachers and some 
relatives. We still didn't give up though, and eventually, by 
sending out several letters to CoCoists across the U.S. and 
Canada, we got our first contributing editors. There were 
also some who were willing to occasionally submit pro- 
grams and articles, which helped out a lot and allowed us 
more time to work on giving the magazine a better look. We 
got away from using markers and relied heavily on the word 
processors while still trying to build our knowledge of 
BASIC. You can actually tell by looking at our first issues 
that we didn't know BASIC all that well; a keen eye would be 
able to spot our improvements as the years progressed. 

In an attempt to improve business by covering a broader 
market, we started to include Commodore and Apple 
material (we didn't yet have enough money to advertise 
much further than the local area). This did help some, but we 
eventually gave that up and went back to an all CoCo 
pubUcation. During this time we were able to place a small 
classified ad in the November 1989 issue of Computer 
Shopper. In about two weeks, the ad paid off with the 
addition of about 25 more subscribers. A few months later 
we placed another ad and got another 20 subscribers. Many 
more people had heard about us and as far as we were 
concerned business was booming! 

Our next ad went into the March/ April 1990 (last) issue of 
CoCo Clipboard. At the end of 1990 we sent out 1000 
flyers direct mail in conjunction with CoCoPro!. We found 
the direct mail advertising method to be the most effective 
as it brought in many more subscribers and contributors. In 
June of 1 99 1 we decided to change the name of the magazine 
to Color Computing because TRS-80 was a registered 
trademark of Tandy Corporation. By this time we were able 
to get access to a Macintosh and a laser printer to give some 
of our pages a more professional look. 

After five long years of supporting the CoCo, we were in our 
senior year of high school and both realized that it would be 
impossible to continue the magazine once we graduated. We 
were both planning on going to college and there was just no 
way we could go on. PubUcation ended in October 1991. 

page 100 

Tandy's Little Wonder 

Around the same time as the demise of the magazine, we 
were informed by one of our former teachers that a couple 
of elementary schools still had the CoCo lab. When the 
actual lab was dismantled, the TVs were given to the teachers 
and the CoCos stuffed into a closet. The teacher decided she 
wanted to use them in her class. She went around an collected 
all the TVs and got the keyboards out of the closet. Having no 
idea what to do with them, she asked around for assistance. 
She ended up contacting one of the junior high teachers who 
had subscribed to our magazine. He told her how to get in 
touch with us. It so happens that the teacher wanting to use 
the CoCos was our former first grade teacher! 

She contacted us and we agreed to go down to the school and 
show her how to use the CoCos. After a few hours work, we 
asked if she would like us to come in and show some of the 
kids how to use the computers. She thought that was a 
wonderful idea. Joe and I couldn't believe it! We were about 
to teach Color Logo on the same Color Computers we 
started with ourselves! 

We went in that week and taught the kids Logo. They were 
amazed at what they could make the machines do and we 
agreed to come back once a week. We even got permission 
from out high school principal to leave school early on 
Mondays so we could teach at the elementary school. 

Now that we are out of high school and in college, we still 
fmd time to go teach Logo and Scripsit to the third grade 
class on the good old CoCos. We even support an after 
school computer club that meets once a week. The children 
are allowed to come in and use the CoCos to play games or 
create/print graphics using CoCoMax or the CoCo Graphics 
Designer during the club "meets". 

The CoCos are all connected to a Network 2 controller. 
This controller allows up to 15 CoCos to be connected to the 
host CoCo via the cassette port (the host must have a disk 
drive). To send a BASIC program to the students, one must 
first load the program into the host. Then all the students do 
a CLOAD. The person at the host will do a CSAVE and the 
program will be sent to all student stations. A disk to tape 
utility is required to send m/1 programs. 

If a student needs to save or print their work, the dial on the 
network controller must be set to the station number that 
will be saving/printing. Then the student CSAVEs to the host 
which is set to CLOAD. When the file is received, the person 
at the host can then save or print it. All this is a little time 
consuming, especially as the students end the day, but the 
system is simple and reliable... and was cheaper than pur- 
chasing disk drives or cassettes for each station. Would you 
like to deal with 15 tape systems, I/O errore and all? There 
are ROMPaks for each station, but most of these are so old 
and worn that not all of them work. It is actually easier to send 
the programs via the network from disk. By using the dial, 
different programs can be sent to each station also. 

Their past experiences with the CoCo have led the boys 
(actually young men now!) into what they study today. Joe 
plans to specialize in teaching computers in elementary 
schools. David is taking computer science courses with 
the goal of majoring in programming and repairing comput- 
ers, and possibly teaching those subjects also. 

Frank Hogg and Frank Hogg Labrotories (FHL) 
EDITORS NOTE: This article was transcribed by myself 
from a tape sent by Mr. Hogg. I apologize for any misspelled 

names and possible misinterpretations. 

The first computer I bought was a 6502 based "Kim 1 " in 
1977 with IK RAM. Tom Spear (a friend) had a SWTPC 
(South West Technical Products Company) 6800 based SS- 
50 bus computer. Well, I got a SWTPC in late 77-78. Dale 
Puckett, who was taking a post-graduate course at Syracuse 
University, was also in Syracuse NY area. We were the only 
ones in the area with 6800 based home computers. We 
exchanged software and developed the systems, and com- 
municated with others around the country with similar sys- 
tems. This lasted until about 1980. 

I run a dental laboratory and bought computers then just for 
the business. We had heard rumors of a Tandy 6809 com- 
puter coming in late 79. I felt that there would be a major 
market for a Tandy 6809 computer with a lot of users. This 
was discussed with Dale, Tom, AlJost (who wrote DynaStar), 
and some others. It was decided that I would expand into 
selling software as the others wrote it. This would provide all 
with added income and tax deductions for new equipment, 
helping to justify hobby expenses. My first ad was a full page 
in the July 1980 issue of 68 Micro Journal selling Dale 
Pucketts' Spell Test (Dyna Spell) and Tom Spears' "Re- 
mote" terminal program. 

The Tandy 6809 machine, the original CoCo, was a disap- 
pointment- only 4K and no expansion. We all had more 
powerful and expandable SS-50 bus 6809 machines running 
FLEX and OS-9. Well, I went out and bought one anyway. 
Richard Hogg, a nephew, had graduated college and was 
working for Bell Labs. He took the CoCo and found that a 
32K model could easily be converted to 64K by adding a few 
wires. Richard wrote an article describing the conversion, 
but didn't want to publish it under his name to prevent any 
possible conflict of interest with Bell Labs. I published 
article under my name, entitled 64K for Free in Color 
Computer News, 68 Micro Journal, and The Rainbow. 

Frank Hogg Labs had licensed FLEX from Technical Sys- 
tems Consultants (TSC) in NC. The 64K upgrade made it 
easier and better to run FLEX and OS-9. Business picked up 
overnight ! We started selling FLEXby the thousands, though 
we had only expected to sell a few. Other companies tried 
to get into the FLEX market, Spectro Systems and 68 Micro 
tried selling versions of FLEX, but weren't successful due to 
lack of supporting software. 

Tandy's Little Wonder 

page 101 

The CoCo 2 was finally introduced with fiill 64K capability. 
Tandy came out with a version of OS-9 for the CoCo 2, 
something I almost had before hand. Ken Kaplan contacted 
me long before Tandy came out with OS-9. We made 
"gentleman's agreement" that FHL would port OS-9 and 
receive a license to sell without paying up-front license fees 
for the work. My crew started work on the port and we ran ads 
in 80 Micro (I think...). Suddenly I couldn't contact Ken. 
After a couple months, Ken finally called and reported that 
a deal had been reached with Tandy and MicroWare 
wouldn't be able to keep the original agreement. I guess we 
could have raised a law suit, or made a lot of noise about the 
deal, but decided against it since nothing would really be 
gained. Instead, we used our advance knowledge of OS-9 and 
the CoCos' limitations to develop some software. The first 
we developed was the O-Pack utilities for Level I. 

The CoCo running Level I was pretty useless.... only 
40K left after loading OS-9. Most people writing about 
OS-9 and all it's glories were actually using Level II ma- 
chines (usually a GIMIX). They were really writing about 
Levelll! You just couldn'tdo much withOS-9 in 64K. FLEX 
only used 8K, so was a better fit to the CoCo hardware. One 
could do more... software was more capable and had more 
memory to work with. 

I was sort of misunderstood in the Rainbow columns I 
wrote pitting FLEX against OS-9... maybe that was my 
fault for not being clear enough! Those articles were really 
not against OS-9, as I was running a Level II GIMIX system 
with nine terminals in the dental lab business, but simply that 
OS-9 Level I left much to be desired on a 64K CoCo with 32 
column screen. One had to go out and purchase 0-Pack or an 
80 column board to get more than 32 columns, and most 
software required 40-80 columns. Multi-tasking/user capa- 
bilities were extremely limited in the 40K left on a 64K 
CoCo! FLEX left more resources for programs. We weren't 
running FLEX on the GIMIX because it wouldn't do the job 
as well as OS-9. We weren't running OS-9 on the CoCo due 
to same reasoning. I took a lot of heat about that stance! 
People STILL remember those articles and assume they are 
anti-OS-9. If FHL wasn't so heavy in OS-9 now, they prob- 
ably wouldn't though! With 128/512K, the CoCo 3 was 
much better suited for OS-9 and support for FLEX dropped. 

I first got involved in 68000 computers in 1984. Mike 
Spit at Hazelwood Computer had designed a 68008 single 
board computer with 128K RAM (could upgrade to 512K) 
that ran OS-9. This board sold for just under $ 1000. That was 
a good price for the time. The only other 68000 based 
computers were from Hazelwood on a SS-64 bus (extended 
SS-50) and sold for $4,000-5,000. The new board was called 
Uni-Quad. Since FHL was selling hardware for the CoCo 
and OSK software, Mike thought we might be interested in 
selling the 68008 computers. He sent one, and we called it 
the QT (Quad Terminal ... for four serial ports). 

I was advertising in 16-17 magazines .. full page ads. The 

cover of the QT brochure was used for a single page Rainbow 
ad. We sold 3-4 QTs the FIRST DAY the Rainbow ad came 
out! The QT sold for $3,000-$3,500 with a hard drive, and I 
was surprised at how many sold. We followed with the QT+, 
which had a 68000 processor instead of a 68008 (68008 has 
8bit bus, 68000 16bit)andupto 1MB. Then cametheQT20 
from GIMIX. The QT20 didn't sell well due to the high price, 
like all GIMIX systems. GIMIX had intended to take some 
of Hazelwoods business with the QT20. The QT20X was the 
first 68000 board designed to fit in a PC case (before the 
PT68K sold by Delmar). This form factor allowed the use of 
low cost, readily available enclosures, not custom made 
ones. This was followed by our K bus systems. 

At the 1989 Rainbowfest in New Jersey, Kevin DarUng and 
some others asked me to stay for a few minutes after the 
show for a conference Sunday afternoon. I was told that 
Tandy had definitely discontinued the CoCo 3. Kevin and a 
group of OS-9 programmers hadbeen working on an upgrade 
to OS-9 Level II, which was sort of in limbo without Tandy 
support (the upgrade was being done for Tandy). I suggested 
that a CoCo 3 upgrade COMPUTER be developed, some- 
thing to get the CoCo OS-9 users into the 68K world. There 
wasn't enough OSK software around and what was out was 
to expensive for most CoCo users. You also couldn't do as 
much with a 68K machine at the time due to lack of software. 

I talked with Kevin Pease and Kevin Darling about making 
a 6809 based computer. I wanted to use the K-bus because it 
was an existing bus and FHL already had products for it. 
Kevin Pease bowed out because he didn't think the K-bus 
was the way to go. Paul Ward called and wanted to form a 
committee to develop a 68K based OS-9 platform. FHL had 
been involved in developing many computers, and I knew 
that the committee method wouldn't work well, as no one 
usually agreed on anything, and by the time everyone had 
compromised, you had a hobbled system. I didn't want to 
work with Paul for that reason. 

IMS was formed shortly after by Kevin Pease and Paul 
Ward, who then started promoting the MM/1, which at the 
time was non-existent. The reality is that IMS may have done 
some damage to the market, as they were promising com- 
plete compatibility with all OSK systems and the CoCo but 
never delivered. The MM/1 actually shipped much later, and 
many users waited months before they had complete sys- 
tems. FHL got many calls from shoppers asking if the FHL 
system would do all the MM/1 was advertised to do. The 
answer was no, and neither would the MM/1 . Many people 
waited to see what would happen instead of buying systems, 
and there was a long wait from IMS. Part of the problem was 
lack of business experience within IMS. 

The TC9 was originally designed to be a direct CoCo 
compatible machine with the ability to upgrade to a 68K 
processor at a later date. The idea was to get a lot of people 

page 102 

Tandy's Little Wonder 

into the upgradable TC9 and then into OSK. The resuh would 
have been a few thousand more OS-9 users out there. Instead, 
FHL had to compete with (undelivered) promises of CoCo 
compatibility from a non-existent machine. This caused us 
to change our marketing. 

Mike Smith and I talked (in July 90) about using the same 
chip set of the MM/1 (68070 and VSC) in the form factor of 
the original QT. This would allow upgrading the QT and 
provide a low cost board to sell CoCo users directly. Design 
started well after the MM/1 design, but came to market well 
ahead of it. This was the TC70. The TC70 was a 16 bit 
machine, while FHL had been working on 32 bit models- 
essentially a step backwards. The design was priced to be 
competitive with the MM/1 . I was going to go with Kevin 
Darling's K-Windows, but Steve Adams' J-Windows 
was a more mature product so I went with it instead. 

In July 1992, we started with the concept of a new computer. 
Mike had 2 68030 32 bit machines on the market, the PC- 
30 (QT-30) and PC-30-16 (QT-30-16). These were some- 
what successful, the QT-30 was made for Washington Uni- 
versity and had a PC/XT 8 bit bus, similar to the PT68K sold 
by Delmar. This taught us that interfacing to all those PC type 
cards wasn't very easy! Documentation was difficult, some- 
times impossible, to get- making it hard to write proper 
drivers that would work with the low cost cards on the 
market. We ended up (like Delmar) with support for only a 
few cards... software support was horrendous! OSK is a bit 
more fussy about what is connected to it, the drivers have to 
know EXACTLY what is there. Each card had to be reverse 
engineered individually to create proper drivers. 

The new machine was originally going to use the PC/AT 16 
bit bus. We started working on the design with that in mind. 
At this time, the "local bus" was being talked about in the PC 
market, which was a 32 bit bus. Mike did a study on support- 
ing the AT bus. Supporting it would take a LOT of board 
space. Not supporting the AT bus would bring the cost of the 
motherboard down enough to provide serial, SCSI, floppy, 
parallel, etc. ports. 

The AT bus was only 16 bits and only operates at 8MHz 

(editor: Some AT class 386/486 machines do use faster bus 
speeds, but the ISA standard is 8MHz to maintain backwards 
compatibility with original AT cards.). The ports built into 
the motherboard wouldn't be limited to 8MHz operation. 
We therefore decided to scrap the PC/AT bus support idea. 

The video cards from FHL are 32 bit, run up to 33MHz, 

have mouse port (serial), keyboard port, high quality sound 
and video for around $300, similar to the price of high 
performance 32 bit PC cards. Since these cards were stand 
alone meant that more than one could be installed. Each 
card could support a separate user with full 32 bit video and 
multiple windows. 

The computer design finalized in August- the Kix-30. The 
design fell into place very easily. The board fit into a PC case 
easily using standard cables and connectors. The first boards 
came in at 10:00a.m. on a Friday early in October and a 
computer was running that same day (this was a prototype 
board! ). The prototype board actually only needed six jumper 
wires to correct minor errors. From conception to finished 
product only took four months. No committee could have 
agreed on anything by that time! The fewer people involved 
in designs like this the better. Keeps cost down and reduces 
compromises to a minumum. 

After the Klx, the TC70 lost interest. TC70 was slower than 
the Kix30, and cost more to expand. Since our supply of 
boards was low, as well as interest, the TC70 was dropped. 
There is actually very little difference in cost between the 
TC70 and Kix30 (Kix is a couple hundred more for a 
complete system, but is 52.5 times faster than a TC70). The 
Kix is so good that the other QT products were dropped also. 
The Kix can be configured for any system, so there was no 
need for any other boards. 

CoCo sales had degraded so much by January 1993 that 
support was more trouble than it was worth. Sales averaged 
only 1-2 per month. The remaining CoCo people seem to be 
in two categories: 1) happy with what they have and love the 
CoCo.. appreciate anything that you do to help them, and 2) 
those just looking for a bargain, who don't want to pay fair 
prices for expensive hardware. Current plans are to put 
the FHL 6809 material out as unsupported shareware. 
This is sort of on the "back burner"., will be done eventually. 

There is still TC70 support, as some industrial users still 
have requirements for the cards, but this is dwindling. Many 
industrial customers are converting to the more powerful 
Kix30. FHL is "market driven"., we build and sell what 
customers want. Some of the larger companies (Apple, IBM, 
etc.) will do surveys then build what they think the customers 
want. If they make a mistake, they dump the products at a 
lowered price and start over. We can't afford those tactics! 

What should CoCo users go to? Well, many bought the 
CoCo because of low cost. The OSK machines, the better 
ones, are rather expensive ($1500-$2000). A PC may be a 
better choice for those people when/if they want to upgrade 
to a faster machine. For the OS-9 user, the OSK machines 
are definitely the way to go. Anything else with the power 
of the OSK machines would cost much more. It really 
depends on what a person wants to do with their computer. 

The OSK market is now back to the "pre-CoCo days" where 
there is more camaraderie, with people in the OSK world 
more appreciative and less demanding. Now there is a very 
powerful 68030 machine rather than the CoCo. This is a 
better market to deal with, going into unknown territory. 

Tandy's Little Wonder 

page 103 

Computers are more of a hobby than a business for me. 

I am very happy with the Kix30.. . don't know what I would do 
different if designing it over again. The next computer will 
be a 68040, but not anytime soon, as the Kix does all we need 
it to do and the 68040 processor chip alone is currently 
$800. 1 don't think there would be much market for the price 
we'd have to charge. 

We are finishing a VGA card for the Kix now. The current 
VAK card (Video/Audio/Keyboard) advertised was designed 
to be compatible with the TC70 and MM/1 (software). We 
thought it would attract some MM/1 users to the more 
powerful 68030, but don't think any have been sold to MM/ 
1 users. All who did buy would rather have VGA based video 
rather than the more limited VSC based card. Rather than use 
the VGA chip set (would be to slow), the FHL board uses a 
design that would write 64 bits to video memory at one time, 
filling the screen up to 40 times per second, which is 
animation speed. The card itself is 8 bit and supports 640x480 
resolution ONLY. It also has a palette controller that allows 
16 million colors. We are currently investigating SVGA and 
planning to market a board later in the year. One problem 
may be that the 32 bit SVGA chips may not be fast enough to 
run with the 68030. 

FARNA Systems by F. G. Swygert 

It seems that some story about the company that published 
this book is in order. My father had been working on our 
family genealogy and asked me if there was a program for the 
CoCo. We tried using one published several years ago in 
Rainbow, but it wasn't quite powerful enough to be much 
help. I then searched the PC SIG database on Delphi for a 
BASIC genealogy program for the IBM PC. I found one by 
the name of "Genealogy ON DISPLAY!". Equipped with a 
general knowledge of BASIC on both the CoCo and IBM PC 
(GW-BASIC or BASIC-A), and "BASIC Program Conver- 
sions" (HP Books), I proceeded to "convert" the program to 
the CoCo. 

There is a good reason "convert" is in quotes... it isn't the 
correct word! GW-BASIC has several keywords unavailable 
to the CoCo, variable names can be up to eight characters 
long, and the memory limit is around 60K, not the CoCo's 
32K. Genealogy ON DISPLAY! was made up of twelve 
individual modules. Each one had to be totally re-written to 
work on the CoCo 3. It wasn't an easy job... I finally com- 
pleted the work after a year of on and off laboring. My father 
would start using each module as it was finished, so the 
programs were thoughroughly debugged. Few bugs found 
there way into the commercial vewrsion, which was ready 
for the public in early 1991. I had thought of uploading the 
program to Delphi early on, but I wasn't about to give away 
that much work! 

So I started selling the genealogy program early in 1992. I 
ran my first ad in The Rainbow that May. Up until this time, 
I had been involved with installing point of sell and other 
business programs for small businesses. There wasn't much 
work for a small, part time operation in this field, so I turned 
my attention to my real love, the CoCo. 

I got my first CoCo thanks to my first hobby and a Timex 
Sinclair 1500. My first hobby is old cars, specifically 
sixties AMC/Ramblers, my personal driver being a 1963 
Rambler American. I wrote and published a book on the 
history of the AMC Rambler using a typewriter. This lead 
me to realize a computer would be much easier for that type 
work! Due to limited funds, an IBM PC was out of the 
question (this was about 1985, nd XT compatibles were still 
priced over $1000 with dual floppy drives and a mono- 
chrome monitor). 

I was first interested in the Sinclair ZX-80 because of the 
low price... I remember the magazine ads in 1980 for the 
$99.95 kits. I saw the T/S 1500 in a pawn shop for $50 and 
bought it. I also purchased a couple books on the little beast. 
I wasn't much of a typist, so the small calulator type keys 
wouldn't present to much of a problem. The entire unit was 
only 81/2" wide, 5 1/2" deep, and 1 1/2" thick, with all of 1 6K 
RAM. I soon found one fatal flaw in the 1500. It used a bit 
by bit printer port that was designed for the little 40 column 
T/S printer ONLY. No full size printer could use that port, 
and a serial printer interface would cost $100. 

Well, I determined I could get another small computer for 
that price, as the bottom had fallen out of the "home com- 
puter" market and TI99/4A computers were being sold in 
department stores for $49.95 (around 1985). I did some 
more research this time around, and decided that of all the 
small computers, the Tandy Color Computer 2 was the best 
all around. Not only did it have a serial port that many 
different printers would interface with, but the disk drives 
were standard IBM type units except for the controller. I 
soon located a used CoCo2 for $100... about half the cost of 
a new one. 

I started out with a cassette recorder and the Scripsit car- 
tridge. The main problem with the cartridge was the lack of 
an ASCII save feature. I purchased a copy of Telewriter 64 
on tape and was in heaven! I then ordered a surplus IBM PC 
jr. thermal printer and made a special cable to adapt it to my 
CoCo. I only paid $49 for that printer. It required thermal 
paper, but was full size. 

I eagerly sought all the information I could on my new 
computer. In many ways, it was just like my Rambler... 
simple, durable, and efficient, doing its' required job with 
few problems. I got a subscription to Rainbow, and bought 
a couple boxes of older magazines from a friend who was 
switching to an IBM compatible. Isaw no reason... my CoCo 
(by now a CoCo 3 and RGB monitor) did all I needed. 

page 104 

Tandy's Little Wonder 

I completed my second book, a complete history of all AMC 
products, on the CoCo 3 in 1992. The ASCII files were 
transferred from the CoCo (written with Simply Better) to 
a Macintosh at a local copy shop. The book was then as- 
sembled using PageMaker and printed on a laser printer. The 
text quality was exceptional, especially when compared to 
that first work. It was this book which kept the ads in Rainbow 
going, as the ads were expensive and software sales weren't 
up to justify the cost, though the software was moderatly 

Falsoft had announced a history of the CoCo, but then told us 
they wouldn't be printing due to unexpected problems the 
authors were having (health problems), but they would re- 
consider if another author was found. About six months after 
this, about a year ago now, I had finished my AMC book. 
Since I'd have the time to write about the CoCo now, I gave 
Falsoft a call. I was asked to send in my ideas and a sample 
of my writing. The idea at Falsoft was to make a compendium 
of recollections from long time CoCo users, the pioneers of 
the CoCo as it were. In my opinion, what the CoCo commu- 
nity really needed was an all encompassing reference, not 
just a simple history. Support was floundering all around us. . . 
we needed a collection of all those valuable tid-bits of 
information that would be helpful to all users! Falsoft turned 
my ideas down by merely saying they were no longer inter- 
ested in publishing the history. At that point, I dteremined to 
go ahead and write this book, it should be noted that had 
Falsoft stated that they were interested in printing a history, 
but not my ideas for a complete reference, I would have been 
willing to go ahead with whatever they wanted. In a way, I'm 
glad it didn't turn out like that. 

When The Rainbow hit an all time low of 16 pages, I was 
greatly concerned about future CoCo support. I wrote 
Mr.Falk a letter expressing an interest in possibly buying out 
Rainbow. About a week later, I got a call from him. We talked 
a while, and it was apparent I couldn't come up with the funds 
he felt he would need for The Rainbow. About two weeks 
passed and I received another call from Mr. Falk. They were 
getting ready to cease publication of the Rainbow (this was 
in February of 1 993), and would consider a sum much lower 
than he had originally mentioned. This lower amount was 
somewhat attainable, so I discussed the idea with several 
potential investors. The outcome of these discussions was 
that they didn't think it was a reasonable risk, $90-100,000 
would be invested in all, but they would be interested in 
helping to support a new magazine. 

I gave the idea of starting a magazine from scratch some 
thought. With the support of several influential CoCo 
people, I decided it could be done. I contacted several 
people who had publiched small CoCo publications in the 
past. All had ceased publication, but all were also willing to 
give much helpful information. 

With my research in pricing and pulishing in mind, I formu- 
lated plans to start a new magazine. In order to survive, the 
magazine would have to leave the door open for OS-9 and 
OSK support, but for the present and immediate future, 
CoCo Disk BASIC support would be the priority. The tittle 
was finalized as "the world of 68' micros" (all lower case., 
"micro"... letters), with a sub-heading spelling out "Tandy 
Color Computer, OS-9, OSK". This would prevent the 
necessity of a future name change. 

As stated, the primary goal of "68' micros" would be support 
of the Color Computer. To begin with, the target would be a 
CoCo BASIC content of around 70% with the remaining 
30% coverage for OS-9 and OSK combined. In all fairness, 
articles that pertained equally to all operating systems would 
be included in the CoCos' 70% (such as Bill Sgambatis' "C 
Programming" series, which is based on the "CoCo-C" com- 
piler, but can be used with ANY compiler.). Also, the 
percentages would have to change with the subscriber base. 
As long as a high percentage are CoCo BASIC users, the 
content for those will remain high. As people move away 
from the CoCo, something that is inevitable, then a higher 
percentage will be devoted to OS-9 and OSK. I expect the 
CoCo BASIC users to keep at least 50%) of the magazine for 
the next five years... I myself am primarily a DECB user! 

The percentages will be based on reader surveys, which will 
be done yearly and when one sends in a subscription form. 
Basing the percentages on mail won't work. I've been in- 
volved in the AMC car hobby for some time now. The clubs 
have splintered into two major groups fighting over perfor- 
mance car coverage (0S-9/0SK) and one supporting only 
the family type cars (DECB) buih from 1958-1969. The 
groups ended up splitting because there are fewer perfor- 
mance cars than average Ramblers. Yet, the performance 
people were outspoken and kept demanding more newsletter 
coverage. The Rambler group finally split off because these 
people were more content with the newsletter and there cars, 
but 20%o of the club was demanding more than 50%o of the 
newsletter coverage. CoCo users parallel the AMC groups. 

This will be an open, reader oriented magazine. In some 
ways, it will be similar to Rainbow. The big difference will 
be response to reader input. My plans are to include readers 
in the evolution of the magazine as much as possible. While 
I won't be disclosing any exact financial information, read- 
ers will know where there investment (subscription) stands. 
A separate account will be kept with enough funds to finish 
the subscriptions paid for. If for any reason publication must 
stop, there will be adequate funds to either finish out the 
existing subscriptions or provide refunds. If this should 
happen, subscribers will also know several issues before the 
end if at all possible. There will be no sudden "this is your last 
issue" headline! It just isn't fair to subscribers. 

I'm out of room! If there are any questions about "68'micros", 
please contact FARNA Systems or see the display ad. 

Tandy's Little Wonder 

page 105 


even more useful information 


Color Computer Users Guide ByLeeDeuell 

EDITORS NOTE: The following guide is a "quick and dirty" 
run-down of using a Color Computer. Lee wrote this for the 
person who will inherited his CoCo 3 system (when that time 
comes!). It was edited to include CoCo 1/2 information also. 
Feel free to photocopy this article and keep it or send it with 
a CoCo that finds a new home! The un-edited version is 
available for downloading from Delphi. 

The CoCo 3 has 57 keys. Uppercase and lowercase are toggled by 
holding down the SHIFT and keys. The F 1 , F2, and ALT keys are 
not used by most programs. The BREAK key is used to halt operation 
of some programs (most programs automatically end.). The CoCo 1 
and 2 do not have Fl, F2, ALT or CTRL keys (53 keys). Most 
programs for these use the CLEAR key for a control key when 
necessary. CLEAR will clear the screen under BASIC forallCoCos. 
See the manuals for more information. 

On the rear of the computer are 10 connections and buttons (8 on 
CoCo 1 & 2). From left to right (as viewed from the rear) are the 
following: Reset, Audio (CC3 only), Video (CC3 only), Channel 
selector, RF out (for TV), cassette. Serial I/O (input/output). Right 
joystick. Left joystick, and Power. Always use care when plugging/ 
unplugging cables ! 

The Reset button is used to end some programs. Also, after some 
machine language (ML) programs (ones that have a ".BIN" after 
their names on the disk or tape) cause strange things to happen to 
CoCo when you exit them. Pressing reset should remove the pro gram 
completely from memory. If not, power down the computer for a few 
seconds. For a CoCo 3, hold ALT and CTRL down, then press reset. 
Let go of all the keys. A screen with three people on it will appear. 
These men helped design the CoCo 3 . Finally, press reset again, and 
you will get the start-up message and RAM will be cleared. 

The CoCo 3 Audio and Video ports are used to connect the CoCo to 
a composite monitor. An RGB monitorport is located underneath the 
computer. Be careful when moving the CoCo 3 if the RGB cable is still 
connected! It's fragile, so don't plug/unplug it often. 

The Channel Selector switch is used to select either Channel 3 or 
Channel 4 when using a TV with the computer. 

The RF Out port is used to connect the CoCo to a television set. Some 
games written for a CoCo 1 or2use colors not displayable on anRGB 
monitor due to the way the colors are derived by the programmer (he 
actually "cheated" with some fancy programming to get more colors). 
The Cassette port allows one to connect a cassette drive (tape 
recorder) to the CoCo. Disk drives are much faster for storage and 
retrieval, plus files (programs) are easier to find on disks. A regular 
audio tape recorder with facilities for an external microphone and 
remote control will work nicely. The volume setting may have to be 
played with a bit to get it exactly right. The cassette port is also used 
to connect the hi-res interface to a CoCo 3. 

The Serial port is used to plug in a printer or modem cable. Only one 
of these can be attached at a time. A two-position switch or cable 
which allows connection of both peripherals at the same time can be 
used. Only one of the peripherals may be actually used at once though. 
A "parallel" printer must use a serial-to-parallel interface (another 
interface! ) to be connected to the CoCo. These interfaces can run at 
a variety of baud rates. The CoCo must, of course, be set at the same 
rate as the convertor or serial printer. This is accomplished with a 
POKE 1 50,x either entered from the keyboard, or put in a program, 
where "x" is 1 80 for 300, 87 for 600 (the rate normally used on power- 
up),41 forl200, 18for2400,4for 4800, orl for9600 baud. Consult 
your serial printer manual for the correct baud rate (most run at 2400). 
Parallel interfaces can usually be run at the highest speed, though not 
much difference will be noticed over 2400 baud. Commands to print 
to the printer are issued like this: PRINT #-2,"THIS WILL PRINT 

Some games andotherprograms use thejoysticks (or a mouse). They 
plug into the left and right joystick ports. Some CoCo 3 specific 
programs require the hi-res joystick interface. This plugs into the right 
joystick port and the cassette port, with thejoystickthenplugging into 
the hi-res interface. The hi-res interface cannot be used unless 
specified by the program as special programming is required. 

Use the Power button to turn the CoCo on and off Always turn the 
computer on after all other peripherals, and off before them. If all 
peripherals and the computer are connected to a multi-outlet surge 
protector or power strip, all may be left on all the time, turning all on 
and off with the surge protector or power strip switch (a surge 
protector is highly recommended!). 

The expansion port on the right side of the computer is used for 
program packs, the disk controller, a multi-pak, or one of several 
available peripherals. Always make sure the system is off before 
inserting or removing anything from this port! The computer could be 
seriously damaged if the item in this port is moved much during 
operation! The Multi-Pack Interface (or MPI, for short) allows 
connecting more than one programpackorperipheral to the expansion 
port at once. 

When using the MPI the disk drive controller must be in Slot 4 . Most 
other items can reside in any slot. Slots can be selected by either setting 
the switch and pressing reset, or by typing POKE 65407,x (where x 
isOforSlotl, 17 for Slot 2, 34 for Slot 3, or 51 forSlot4). 

The controller for the disk drives is inserted into the Color Computers' 
cartridge slot. It contains the Disk BASIC ROM or a ROM for another 
DOS (Disk Operating Systems). Disk BASIC is often referred to as 
"RS-DOS" (Radio Shack Disk Operating System), but this is a 
misnomer! The Disk BASIC ROM contains additional BASIC com- 
mands that simply allow BASIC itself to access information on the disk 
drive. OS-9 is an example of a true DOS, as is MS-DOS (Micro Soft 
DOS) for IBM compatibles. Even A-DOS, a popular Disk BASIC 
enhancement, is not a true DOS . DiskB ASIC is available immediately 
upon starting the computer, whereas most DOSes have to be loaded 
from disk. 

page 106 

Tandy's Little Wonder 

The CoCo is capable of usingup to four single sided disk drives, though 
most people only use two. Up to three double sided disk drives may be 
used (Tandy used the side select hne forthe fourth single sided drive), 
though only OS-9 is really capable of fully utilizing double sided drives. 
Several programs and disk BASIC enhancers (notably A-DOS) will 
allow accessing the back sides of double sided drives as if they were 
additional single sided drives (therefore, two double sided drives could 
be treated as four single sided drives). The Tandy disk controller is 
capable of handling drives with a capacity of up to 720K, both 5 .25" 
and 3.5" types. Disk BASIC enhancers or OS-9 must be used to 
access the larger drives. Under disk BASIC, drives are numbered 
from to 3 instead of 1 to 4 or A to D. Always make sure there are 
no disks in the drives when the computer is turned on or off. A stray 
signal over the cable sometimes erases or changes the data directly 
under the drive head(s)! 

To runprograms under BASIC, type RUN "filename (:disk#)" to load 
and automatically run, or type LOAD "filename (:disk#)",R. Use 
LOADM "filename (:disk#)" followed by EXEC (after loadis finished) 
to execute (run) machine language programs. If no disk number 
isspecified, drive number is assumed by Disk BASIC. Cassette 
systems are similar, except with a "C" appended to the front of the 
command (CLOAD, CLOADM) and no device number is needed 
(there is only one cassette recorder!). 

Mostprograms include a way forthemto automatically end. Oneway 
to stop a program that is running is to press the BREAK key. As a last 
resort you can press the reset button on the back. Be careful when 
using reset, however, as it can erase a program that is in memory or 
on a disk in the drive. If a program asks you on the screen if you wish 
to quit or end the program, you may need to press SHIFT and "y" (yes) 
or "n" (no), as some programs only recognize capital letters. 

I think this is enough infomiation to get you started using the Color 
Computer. I don't want to tell you everything! If you have any 
problems or questions, get in touch with one of the computer clubs 
hsted elsewhere in this book. Also, don't forget to read any manuals 
or books you may have with your system. The Library listing and past 
magazines should help also . Good luck, and happy Color Computing ! 

Serial Interface Specifications 

Looking at the connector from the back of the CoCo: 

Cassette Interface 


1 Carrier Detect (status input) CD 

2 Recieve Data (to computer) RD 

3 Ground (0 voltage reference) GND 

4 Transmit Data (from computer) TD 

Suggested input playback level- 1-5V peak-to-peak 
with a minimum impedance of 220 Ohms. 

Typical output level to recorder- 800mV peak-to-peak 
at IK Ohms. 

Remote switching (relay) capacity- O.SAat 6V (max.) 
Looking at connector from back of the CoCo: 



Remote Control 

Signal Ground 

Remote Control 

Input (from recorders' EARphone jack) 

Output (to recorders' MIC or AUX jack)* 

* Radio Shack CTR and CCR recorders use the AUX jack, 
"generic" recorders use the MIC (microphone) jack. 

Joystick Interface 

Looking at connector from back of CoCo: 



Right/Left comparator input 

Up/Down comparator input 


Fire button 1 ; high/open, low/closed 

+5V DC, 0.5A 

Fire button 2; high/open, low/closed 

Baud rate is changed by typing "POKE 150,x" where "x" is: 
BAUD Rate Decimal Hexadecimal 






















Tandy's Little Wonder 

page 107 

RGB Interface 

ASCII Character Codes 

Looking at the connector under the CoCo (cable exits 
from under the computer at pin five): 
9 7 5 3 1 

10 8 6 4 2 














Polarity (no pin) 




Horizontal Synchronization 


Vertical Synchronization 



Cartridge Port (Expansion) Connector 

Looking "in" at the connector on the CoCo, odd numbered 
pins are on top from right to left, even numbered pins on 
bottom from right to left (39&40 on left, 1&2 on right): 


1 -12V, 100mA (CoCo 1 only) 

2 +12V, 300mA (CoCo 1 only) 

3 HALT input to CPU (normally low) 

4 NMI (non-maskable interrupt, normally low) 

5 RESET to CPU (normally low) 

6 E clock signal (main) 

7 Q clock signal (leads E) 

8 CART (cartridge detect interrupt, normally low) 

9 +5v, 300mA (all models) 

10-17 D0-D17 (consecutivly numbered, data bits) 

1 8 R/ W (read/write signal to/from port, high on write) 

19-3 1 A0-A12 (consecutivly numbered, address bits) 

32 CTS (cartridge select, normally low) 

33-34 Signal ground 

35 Sound output 

36 SCS (spare cartridge select, nonnally low) 
37-39 A13-A15 (consecutivly numbered, address bits) 

40 SLENB (disables internal device selection, nor- 
mally low); allows decoded but unused sections of 
RAM to be used by external devices. 

Display characters by typing "PRINT CHR$(xx)", where 
"xx" is the decimal code. 32 column screen (CoCo 1/2) 
only displays codes through 122. 

Character Decimal Code 





































































Up Arrow 





(+SHIFT)91 ([) 






(-hSHIFT)93 (]) 














Codes 128-159 are mostly European accent marked characters. 
They are not printable with a CoCo 1 or 2. 

page 108 

Tandy's Little Wonder 

BASIC/Extended/Disk Error Codes 






Syntax Error 






Out of Data 



Illegal Function Call 






Out of Memory 



Undefined Line 



Bad Subscript 



Redimensioned Array 



Divide by 



Illegal Direct 



Type Mismatch 



Out of String Space 



String too Long 



String Formula too Complex 



Can't Continue 



Bad File Data 



File Already Open 



Device Number 



Input/Output Error 



Bad File Mode 



File Not Open 



Input Past End of File 



Direct Statement in the File 



Undefined Function Call 



File not found 



Bad Record 



Disk full 



Out of buffer space 



Write protect 



Bad file name 



Bad file structure 



File already exists 



Field overflow 



Set to non-fielded string 



Verification error 



Write or input past end of record 

Super Extended BASIC Error Codes (CoCo 3 ONLY): 

Code # Description 

HR 3 8 Hi-Res Graphic Error 

HP 3 9 Hi-Res Screen Print Error 

Bank Switched ROM Pak (Activision) 

Some of the CoCo 3 ROM Paks contain more than 32K of 
data, which the CoCo 3 can select directly from the cartridge 
port (the CoCo 1/2 could only use 16K Paks). This is 
accomplished by switching banks of 16K in and out of the 
memory map. This switching is accomplished totally within 
the ROM Pak by two ICs- a 74LS 10 triple input NAND gate 
and a 74LS 1 75 edge triggered quad flip flop. Up to 16 banks 
could be selected by this hardware, allowing ROM Paks to 
contain up to 256K of data. 

Switching is accomplished by writing to the first four bits of 
location &HFF40. This sets the outputs of the 74LS175. 
These outputs control the high order address lines of the 
ROM. At power up or reset, the outputs are all set to zero so 
that the first bank is always selected first. This is done by 
tieing the ROM master reset to the CoCos' reset. Writes to 
any address in the &HFF40 through &HFF5F range will set 
the bank select latch, as no further decoding was done. Note 
that since bank selection is done in 16K increments, this 
same technique could be used with a CoCo2. 


E clock |_ 

R/W I— I" 

GND |- 
















R0MA14 I 

DO I- 
Dl U 

ROMA15 I- 





^ ROMA16(128K) 



The remaining ROM lines are wired as a normal 1 6K ROM 
Pak. D0-D7 of the CoCo is wired to the same on the ROM, 
and likewise with A0-A12. A13 would be connected to 
74LS175 pin 15, but is not used on the Activision ROM 
Paks. It would only be used with larger ROMs. 

Tandy's Little Wonder 

page 109 


CoCo 1 D&E Boards (1 of 3) 

page 110 

Tandy's Little Wonder 



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CoCo 1 D&E Boards (2 of 3) 
Tandy's Little Wonder 

page 111 

CoCo 1 D&E Boards (3 of 3) 

page 112 

Tandy's Little Wonder 

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CoCo 2 (American, 1 of 2) 

Tandy's Little Wonder 

page 113 

«4K HAM IC; ^PO 4I44-I. MM4lt4-| 
Ultl«4-I0P. UCM6«4St.20 

CoCo 2 (American, 2 of 2) 

page 114 

Tandy's Little Wonder 



tXTENO VERSION IC8:TCC1002 (26-3n6A) 

CoCo 2 (Korean A, B is similar, 1 of 2) 
Tandy's Little Wonder 

page 115 

marts : 

O ICn . iC24 «4K UPOIUCC. 

•4K RAAI IC; wr0«*4-2 , HU4a*4-S, MM«4-tO^. HCMCMtfLjZO 

CS) D12/I3 Diode* «rc not uicd wlxn IC7 
80)0527 with dace code tA17 (17tb mck 
of 1984) or titer it uxd. IC7 ao}aS27 
after date code 8417 includaa the 

CoCo 2 (Korean A, B is similar, 2 of 2) 

page 116 

Tandy's Little Wonder 


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CoCo 3 & 512K RAM Board (1 of 2) 
Tandy's Little Wonder 

page 117 

page 118 

CoCo 3 & 512K RAM Board (2 of 2) 
Tandy's Little Wonder 

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Tandy's Little Wonder 

page 119 

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Multi-Pak Interface (small) 

page 120 

Tandy's Little Wonder 

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FD-501 Disk Controller (FD-502 similar) 

Tandy's Little Wonder 












LM339I 1 TP4 





■ 8M12 REGULATOl . 




Ipost; Ireset 






MH 1 









MC6847 VDG 

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Circuit Board Layout, CoCo 1 Revisions C Through E 






MCM529 LM339 

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TP8 • |U16| 









MC6847 VDG 

















MC6887 SAM 




CoCo 1/TDP-lOO Circuit Board Layout, Revision NC (also called "F" or "285") 

page 122 

Tandy's Little Wonder 

iWITC i 


































( :arti idge 
I ;onn: iCtor 



74LS78 I I /IC6809 ! 

American CoCo 2 (Korean models similar) 











IC62J 512K 





{IC36) CN5 








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Tandy's Little Wonder 

page 123 

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GIME Block Diagram 


















MC6809E Block Diagram 

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page 124 

Tandy's Little Wonder 

Software and books for your Color Computer! 

The ONLY CoCo Supporting Magazine Available! 



r^mdvs'UMeWonrier/F.r.Swvgtrt. 1993) $25.00 

Tne most complete and up-to-date reference and history on the Tandy Color 
Compulerl Valuable infoinuition on upgrades, modiRcauons, clubs, vendors, 
hardware, schematics., jnorel 140pages(8.5"xll'',twocolunin) 

Pro ^amminp the 6«(t9 rZa]csiLabiak. 1 9H2) $24.00 

Recommended by Motorola for 6809 machine language programming. 
Written in an easy to follow text book format. 360 pages (6"x8", single col.) 
OS-90ulckReferenceandProgramm er!iGulde .$7.00 

(F.G. Swygerl, 1992) A ready reference to get that bulky OS-9 manual off 
yourdeski Command syntax, system calls, error codei.window codes, morel 

Patch OS.9 : The most used /desireable paidies and utilities for OS-9 Level 
n. Aulo-paich with two 40TyDS drives and 5 1 2K , or send 54 and a copy of 
your original system disk and well install for you. $7.50, or $5.00 with 
purchiseof Quick ReferenceGuide. 

The CoCo Family Recorder: The BEST genealogy database ever for the 
CoCo3 1 Requires 80 c(dumn monitor, two disk drives. $20.00 
invoices. Several reports easily generated. Basic09 source includedl$25.00 
Little Black Bonk : Address/phone/mailing label daubase. $6.00 
VTO : Video Tape Organizer (database). Prints labels (I'xS"). $6.00 
SPECIAL : Get both LiOU Black Book & VTO for only $10.00! 
Crr -wRnaclTT : Tic-Tac-Toe with sound an music, amazing graphics I $10.00 
Mind Games RD: Collection ofgames run from included RAM dsikinS 12K, 
can load/run each also. $10.00 

••*Add $2 ($4 CAN) S&H to each order. GA residents add 5% tax*** 

FARNA SystemslSoftviSiTQ 

P.O. Box 321 

Warner Robins, GA 31099-0321 

^Phone912-328-7859 9:00-12:00 AM EST(evenings and weekendsokayl) 

the world of 



[jTrndv Cdot Cjmpulrr. OS-9. OSK I 

A quality publication supporting the CoCo, Disk BASIC, 
OS-9, and OSK (OS-9/68000). Top writers and articles are 
featured, including the infamous Marty Goodman. Regular 
features include "Beginners Showcase" (short programs 
in CoCo BASIC, Basic09, or C), " The Hardware Hacker" 
(by Marty Goodman), "0S-9/0SK Answers!" (Q&A by 
Joel Hegberg), "Telecom" (network/database news), "Mi- 
cro News" (new products and news), "SwapShop" (sub- 
scriber classifieds- buy, swap, sell soft/hard ware!). Classi- 
fied ads are for subscribers ONLY, .20/word with $4 mini- 
mum (new subs, get 120 words firee, renewals 60, per year). 
Display ads are available for dealers at reasonable rates. 
Subscriptions are $23/year ($30 Canada) for 8 issues, 
one delivered every six weeks, or $12/six months (4 is- 
sues), "micro disk" contains DECB and CoCo OS-9 for- 
mats and is $30/Ye arlv ($42 Canada) or $6 for individual 
copies ($7 Canada)| [^7QFf WITH COPY OF THIS AD! I 

FARNA Systems/6S' micros 

P.O. Box 321 
Warner Robins, GA 31099-0321 

Phone 9 12-328-7859 9:00-12:00 AM EST(evenings and weekendsokayl)^ 

Where do you go for Color Computer hardware. 

At CoNect, you will find only the best hardware and 
software for your Color Computer! Every dollar we 
bring in goes toward the design and development of 
additional hardware, so you know your money will 
continue to support "Tandys' Little Wonder"! 


449 South 90th Street 
West Allis, WI 53214 

(Phone 414-258-2989 Evenings 
& Weekends) 

Mini RS-232 Port: $39.95 

Full featured serial port. Has all signals necessary for 
flow control (missing in some!). Jumpers allow easy 
readdressing and DSR/DCD swapping. Y cable sys- 
tems require power supply... add $9.95 

Y-Box: $29.95; Power Y: $39.95 

You may not need a Multi-Pak! Fully buffered Y cable, 
very reliable! Power Y adds +I-\2V for hard drive 
controllers, etc. Makes expansion cheap and easy! 

Hitachification: $29.95 

Send me your CoCo and return shipping, and I'll pro- 
vide and install an HD63B09E CPU. Runs cooler and 
faster (with OS-9 patches from Burke&Burke or Galse 
Force). 90 day limited warranty, MC68B09E returned. 

Custom RS-232 Cables: $9.95 

Specify ends needed (DB-25, DB-9, 4 pin) and use. 
Can make normal, null modem, or DCD/DSR swapped. 
Six feet long unless specified shorter. 

XPander: $119.95 

This is the ultimate expansion unit! Plugs into the side 
of the CoCo. Mounts two SCS driven (floppy and hard 
drive controller, etc.) devices over the motherboard as 
well as a fully decoded card in the ROM port. ROM 
port can also be used with games! Built-in no-slot RS- 
232 pwrt also, similar to Mini RS-232. Requires modi- 
fied CoCo case bottom (hints included) or perfect for 
mounting your CoCo in a PC case! No soldering 
required, comes with plug-in type power supply. 

CoNect carries a large selection of used 
hard and software. Please write for a cata- 
log. We are also interested in buying used 
CoCo and OSK hard and software, work- 
ing or not. Software doesn't need to boot, 
but must have original manual and disk. 

Tandy's Little Wonder 

page 125 


Quality OS-9 Software for your Color Computer 3 and the MM/1 from IMS 

Variations of Solitaire - A game pack which includes FIVE variations of the popular one- 
person card game Solitaire ! Includes Pyramid, one of the most habit-forming, Klondike, the 
standard version of Solitaire, Poker, which gamblers would enjoy. Spider, where a single 
hand can take hours of play, and the popular gambling variation Canfield. 

Game Pack - A game pack of FIVE popular board games adapted for your favorite computer ! 
Includes Othello, Yahtzee, KnightsBridge, Battleship, and Minefield. 

These two products come for both the Color Computer 3 with OS-9 Level 2 and at least 25 6K 
of memory or for the MM/1 from IMS. Color Computer version is $34,95 and the MM/1 
version is $49.95. (Multi-Vue is NOT required for the Color Computer version!) 

WPShel - This is an impressive tool which allows those who do a lot of Word Processing 
on their Color Computer 3 to put all of their favorite tools under a single point and click 
environment. Requires OS-9 Level 2, system support from the Windlntmo&xAQ which comes 
with Multi- Vue and at least 256K of memory. Mouse and printer are optional but desirious. 
Only $22.00!! 

To Order Send a Check or Money Order to: 


P.O. Box 540 

Castle Hayne, NC 28429 

Phone (919) 675-1706 

North Carolina residents please include 6% sales tax. Shipping is free to the 

Continental US. For Alaska, Hawaii, Canada, and Mexico, add $3 per item. 

For all other locations, add $5 per item. All non-US orders MUST be an 

International Postal Moeny Order in US Funds! 

Call or write today for a FREE catalog! 

page 126 Tandy's Little Wonder 




























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Tandy's Little Wonder 

page 127 

BDS Software 

P.O. Box 485 

Glenview, IL 




CF83 FORTH - A complete language and operating system in one. Fast like Assembly 
Language. Easy to use like BASIC. See article on page 44 

KJV BIBLE - The King James Version of the Bible in ASCII txt files suitable for use with your 
own word processor. Taken from numerical control tapes used to make printed Bibles: no typos! 
Complete KJV Bible on disk - $75. Old Testament only - $60. New Testament only - $20. 
Individual books and 1/2 books are $3 per disk. 

lAVE AND DEATH - 1 or 2 player teiritorial control game. 

We have other software available also- send SASEfor detailed list with prices! 

the most popular CoCo Disk 
BASIC enhancement ever! 

ADOS-3 Plus Extended ADOS-3: 

An Unbeatable Combination for your CoCo 3! 
NOW JUST $49.95 

Receive both programs on disk with configimng utilities that enable 
you to generate a file suitable for burning into a 271 28 EPROM. Return 
the cx)nfigured file to SpectroSystems with S15 and receive your 
EPROM by return mail. Programs may also be purchased separately: 
ADOS-3. $24.95; Extended ADOS-3 (ADOS-3 required), $29.95. 
Adapter for disk controllers with 24 pin ROM socket, $ 1 0. Original 
ADOS for CoCo 1 & 2, $14.95. 

Features of ADC-S: . 

Supports double sided drives; 35, 40, or 80 tracks; 5.25" or3.5'. Fast 
step rates; disk drive head-bangingfixed.Customizestartupmessage/ 
screen width/screen colors/ printer baud rate/ default processor 
speed/keystroke macros; RUNM command; lowercase commands; 
rep)eat/edit of last directmode command; SCAN command lists text 
files to screen or printer, gives start/end/exec addresses for M/L 
programs ; auto line number prompts; MA- monitor; one or two column 
directory with free grans to screen or printer; up/down arrow scroll 
IhroughBASIC programs (right arrow edits current line); FAST and 
SLOW conmmnds (2MHz speed supports disklyO and printing); auto- 
edit of error line after program abort; COPY <filename> TO <drive 
numbcr> with "Replace?" prompt if file exists; more! 

Additional Features of Extended ADOS-3: 

MENU command allows up/down arrow key file selection for run, 
copy, kill, load, rename, etc.; ultra high-speed RAMdisk (requires 
5 1 2K, minimimi); key repeat; fast BACKUPS (twice as fast for fuU 
disks, proportionately faster for partly full disks); B ACKUP-with- 
format; fast DSKINl (format); wild-card COPY and KILL with 
opdonal prompting for individual files; block move or copy a range of 
BASIC program lines. SKIP command allows read/write/ format of 
35/40 track disks on 5.25" 80 track drives. Date (or date/time with 
hardware clock) displayed for files in directory; paralell printer ports 
supported; text-screen printer dump; supports up to 3 double sided 
drives pliK two RAM drives (CONFIG command allows dynamic 
reassigiunent of drive nimibers 0-3 to any of these); All CoCo real- 
time clocks sujjported (driver for Dis to clock, $5 ; for Smart Watch $ 1 0, 
or $5 with purchase of SmartWatch). 

The Smart Watch: 

Real-time clock that plugs into the 28 pin ROM socket (or adapter for 
24 pin sockets). Contains its own lithium batteiy rated for 1 Oyears of 
use. Keeps time independantly of computer. $30 with OS-9 drivers 
included; add $5 for Extended ADOS-3 driver. 


lllllN. KendaU Dr. 
Suite A-108 
Miami, FL 33176 
Phone 305-274-3899 


page 128 

Tandy's Little Wonder 

The C Compiler for the CoCo has finally arrived... 


CoCo-C is a complete RSDOS based C development package for the Color 
Computer not requiring the OS-9 Operating System. CoCo-C consists of five 
main programs: a Text Editor, a C Compiler, an Assembler, and a Library Linker 
which are all controlled by the CoCo-C Command Coordinator. 

Text Editor 

A full featured screen oriented line editor for the CoCo 3 developed by Bob 
van der Poel. Powerful editing and cursor commands with auto-indent and 
user defined macros make this a great editor for writing C or assembly 
language programs. A less sophisticated version for the CoCo 2 is also 

C Compiler 

The CoCo-C Compiler is a full featured K&R style integer compiler 
specifically designed for RSDOS based systems. It has assembly language 
output, position independent code and can output ROM-able code if desired. 
Added features allow you to mix C, assembly language and BASIC 
commands within your program! 


■^ This symbolic assembler is capable of assembling files as large as available 

\ disk space. It supports a Motorola style syntax and outputs standard binary 

,■ files ready for LOADM and EXEC. Options include list file output and 

■" generation of symbol table file. 




The Library Linker is a utility which links the CoCo-C's 90+ function library 
with your compiled binary file, creating a stand alone executable ML file. 

Command Coordinator 


The Command Coordinator is CoCo-C's main program. Its user friendly 
i^ menu driven screen smoothly switches back and forth between the Editor, 

Compiler, Assembler and Linker. 

The CoCo-C Compiler package includes BOTH CoCo 2 and 
CoCo 3 versions of ALL the programs listed above plus MORE! 

Never before has there been an offer like this for the Color Computer ! 


J Requires 64K COCO 2 or 128K COCO 3 Infinitum Techuology 

J Only $59.95 P.O. Box 356 

i Plus $4.00 shipping & handling Saddle River, N.J. 07458 

■■ (check, money order, or COD) 914-356-7688 

fAMfia&aftiMWAVW Tandy's Little Wonder -ViMiAVVMA&VVV" page 129 

QiHimJy.c Vtilif.v Set 1; 

'* optimize ycxjr floppies and hard drives quicldy and easily! •» Includes utility to check file and directory Iragnientation. 

•* Worths alone or with Burke & Burke repack utility. "♦ One slop optimization lor any Level 2 OS-9 system. 

$29.95; Foreign Postage, add $3.00 


» Check and correct any disk's llle and directory structures without any technical mumbojumbo. 

•* Run periodically to maintain the Iniagrity of your disks as well as Itie rellatiilliy of your data. 

~* Especially useful before optimizing your disks. 

$ J 9.95; Foreign Postage, add $3.00 

Optimi/.e IJtilifv Set Pac: 

"» Get both packages together and savel 
$39.95; Foreign Postage, add $4.00 

lIpTimc: A monltily magazine for CoCo's and OSK machines. 

Ill eucli isiiue: iv Find out about new products ami upgrades fur yuur favorite computers. 

ft [jcdm about what new technical brcaklhrougtis arc on the horizon. 

w Discover what programs really can do and what they cannot. 

«•• l^iblished monthly in newsletter format. 

One Year Subscription, two installments ot $7.50; 

Canadian Orders, two installments ot$9.0Q; Foreign Orders, 2 X $1 1.00 

Can also be paid in one installment 

Hufk-Tssiips: From September 1992. Limited supplies. 

$1.50 each; Foreign Orders, add $1.25 each 

Bulk orders ol six or more, $1.25 each; Foreign Orders add $1.00 each 











(— »- 















NInc-Tlmfs: The bi-monthly disk magazine for OS-9 Ixvcl 2. 

In each issue: • Helpful and useful programs 

• C and Basic09 programming examples 

• Hints, Help columns, and informative articles 

• All graphic/joystick interface 

• Can be used with a hard disk or ram disk 
One Year Subscription, $34.95; 

Canadian Orders, add $1.00; Foreign Orders, add $8.00 

Hiirk-lssiic-;: From May 1989. Write for back issue contents. 

$7.00 each; Foreign Orders, add $2.00 each 
Bulk orders ol six or more, $5.00 each; Foreign Orders, add $1.50 each 

MHfa/iiif Sourrc: Full Uasic09 code and documentation for the presentation shell used 
with Nine-Times. 
$25.95; Foreign Orders, add $5.00 




Technical Assistance & Inquiries: 

JWT Enterprises 

5755 Lockwood Ulvd. 

Youngsiown, 01144512 

Copyrlglit (C) 1993 


Foreign postage excludes U.S. Territories and Canada. 
'l"hese products for OS-9 Level 2 on the CoCo 3. Sorry, no 
C.O.D.'s or credit cards; Foreign & Canadian orders, please 
use U.S. money orders. U.S. checks, allow 4 weeks for 
receipt of order. Ohio residents, please add 6% sales lax. 

OS-9 is a tradumark at Mlcrowaro SysLoms Corp. and Motorola, Inc. 

page 130 

Tandy's Little Wonder 


Symbols and Numbers 

128K upgrade 14, 15, 84 

16K upgrade 6 

1MB upgrade 21,22,83 

25 6K Upgrade 84 

285 board 12, 82 

2MB upgrade 83 

40 track 40 

40 tracks 72 

4464 37 

512KBASIC 19 

5 12K upgrade 83 

6309 Patch 86 

64K Screen Expander 1 3 

64K Upgrade 101 

64K upgrade 12 

6502 101 

6551 95 

68 Color Micro Journal 14 

68Micro 9, 11, 101 

68 Micro BBS 12 

68 Micro Journal 6,7, 13, 15, 101 

68008 expansion card 15 

6809 Colour Show 15, 16 

6809E Instructional Kit 14 

68xxx Machines, The 29, 30, 99 

80 Column Card 13 

80 Micro 10, 11, 42 

80 Microcomputing 7 

80 track drives 73 

80 U.S. 7 

A-Bus 80 

AAA Disc Drive Repair 74 

Aardvark 1 1 

Aardvark-80 9 

ClayAbrams 9 

AcBBS 61 

ACTA 95 


ACS 29 

Adam Computer 37 

Steve Adams 103 

ADOS 39, 41, 73 

ADOS-3 17, 42 

Adventure Novel Software 19 

JosephAhern 17, 24, 100 

TimAhrens 7 

Algebraic Notation 45 

Alpha Products 8 1 

Alps 75 

Altair 26 

Amdek 13,71 

Amdisk-III 71 

Amiga 68 

Amtelco 44 

Analog RGB Monitor 65, 68 

Ron Anderson 99 

ANSI C 44 


Apple Computers 15, 19,20, 43, 76, 100 

artifacting 68 

Arzin 12 

assembler, OS-9 47 

assembly language 46 

Atari Computers 6,17,37,68 

ATCoCo 87 

Atlanta CoCoFest 23, 24, 25, 27, 28, 29, 57, 99 

Atlanta Computer Society 23, 24, 27, 57 

Atomtronics 8 

audio amplifier 66 

Cray Augsburg 20,21, 24 

Australia 21, 55, 98 

Australian Rainbow 98 








44, 46, 50 

Baldwin Park 52 

Barcode Reader 

William Barden Jr. 

BarSoft 86 

BASIC 36, 37 

BASIC Compiler 

BASIC conversions 43 

Basic Technology 12 

BASIC Unravelled 14 


Basic09 47, 50 

Basic09 Tour Guide 

baud 58 

BBS 7, 59 

BBS software 

BDS Software 

Belgium 55 

BillBemico 16 


binary 47 

TomBirt 52 

Steve Bjork 24 

Black Sanctum 9 

BlackHawkEnterprises 56 

LeeBlitch 8 

Steve Blyn 25 

Bob van der Poel Software 56 

WaltBolden 9 

Carl Boll 51 

Botek Instruments 1 1 

bps 57 

Brother 75 

Fredrick Brown 99 

Jack Brown 7 

bubble memory 13 

bulletin board system 57 

bulletinboardsystem(BBS) 57 

Tandy's Little Wonder 

page 131 

Burke & Burke 56 

Burke&Burke 18, 19, 25, 27, 29, 30, 56, 74, 86 

byte 47 

BYTE Magazine 6, 7, 12, 34 

C board 6, 82 

C compiler 15,31,44, 50 

C.C. Writer 9 

C.Itoh 75 

California Digital 15 

Calixto Island 9 

Canada 20, 21, 22, 55 

Canaware 56 

CART strapping 78 

cassette 69 


CCHDisk 79 

Cer-Comp 7, 9, 17, 19, 30, 43, 47, 56, 76, 86, 99 

CGA 68 

CGP-115 75 

Bill Chappie 14, 16, 21 

Chicago CoCoFest 29, 30, 51, 57 

Mike & Joanne Chinitis 15 

Chromasette Magazine 8, 9,14,15 


cm Pages 21 

Citizen 75 

clubs 51 

CMOS 29, 85 

CoCo 6, 9, 43 

CoCol 82, 96, 101 

CoCo2 14, 83, 96, 102,104 

CoCo3 16, 18, 20, 26, 38, 42, 68, 77, 78, 83, 84, 96 

CoCo4 23, 27, 36 

CoCoCUpboard 100 

CoCo Magazine 98 

CoCoMaxIII 17 

CoCo MIDI 3 81 

CoCo MIDI Pro 81 

CoCo Newsroom 18 

CoCo-C 31, 44 

CoCo-Link 98 

CoCoFest 23, 24, 27, 28, 29, 30, 52, 57, 99 

CoCoMax 15 

CoCoPRO! 22, 23, 24, 25, 26, 27, 29, 31, 58, 86,100 

CoCoXT 74 

Cognitec 10, 18 

cold start 40 

Coless Computer Design 56 

CoUeco 37 

Color BASIC 37, 38, 81 

Color composite video signal 90 

ColorComputer 5, 6, 34 

Color Computer Magazine, The 13, 14, 20 

ColorComputer News 7, 12, 13, 14, 34, 101 

ColorComputerSIG 11 

ColorComputing 24, 100 

ColorComputing Software 56 

Color Expo 14, 42 

ColorGraphics Plotter 75 

Color Max 3 17 

Color Micro Journal 14, 15 

Color Mouse 14 

Color Systems 56 

Co lorburst Signal 65 

ColorCom/E 10,12,41 

Colorware 7, 15, 17, 19, 20 


Commodore Computers 20, 37, 40,43, 68, 76, 100 

CompiledBASIC 43 

Complete Rainbow Guide to OS-9 16 

composite video 65, 66, 90 

Computer Accessories 11 

Computer Infomiation Services (CompuServe) 7, 11, 12,41,59,61 

Computer Island 25 

ComputerPlus 16, 20, 29, 56 

Computer Shack 14 

Computer Shopper 100 

Computerware 7, 9, 10, 13, 14, 19 

Computize 17 

CoNect 50, 58, 79, 86, 87 

Connection-80 7, 10, 11 

CP/M 10, 11, 14 

Fred Crawford 1 3 

CRC Computers 21 

Jack Crenshaw 99 


H. Allen Curtiss 18, 20, 26, 29 


D board 38, 82, 95 

Daisy Wheel Printer 75 

Robbie Dalzell 98 

Danosoft 20, 22, 27 

KevinDarling 23, 24, 102 

Data-Comp 10 

Datasoft 13, 14 

Mark Davidsaver 10 

Da Vinci 3 17 

Gary Davis 7 

Susan Davis 7 

Wayne Day 6, 7, 8, 11 

Dayton Associates 56 

DC Modem Pak 26, 27, 58, 78 

De-soldering 89 


decimal numbers 47 

DEFT Software 14 

Delmar Corporation 25, 26, 27, 99, 102 

Delphi 5, 19, 23, 25, 47, 52, 57, 58, 61, 69, 86, 88, 104 

Deluxe Joystick 14, 80 

Department of Agriculture, US 6 

Derringer Software 14 

Des Moines, Iowa 52, 57 

DeskJet 29 

DeskMate 17 

Desktop Publishing 20 

desktop publishing 18, 19, 20, 21, 26, 27, 29 

JimDeStafeno 30, 52, 99 

destructive removal 89 

LeeDeuell 106 

Developers Pack, OS-9 47, 49 

Peter Dibble 14, 16 

Diecom Products 17, 19 

DIGInews 16 

page 132 

Tandy's Little Wonder 

DigiSectorDS-69(B) 20, 21, 80 

Digital RGB Monitor 68 

digital logic analyzer 22 

Digitizer, video 15,20,21,80 

direct video input, adding 66 

Dirt Cheap Computer Stuff Company 5 6 

Disk 7, 8, 9, 10, 13, 22, 29, 41, 70 

DiskBASIC 19, 23, 28, 37, 86 

DiskControUer 9, 20, 41, 42, 71, 76, 93 

Disk Drive 40, 93 

Disk Extended Color BASIC (DECB) 37, 38, 48, 50, 70 

TonyDiStefano 7, 11, 12, 21, 22, 83 

Disto 16, 22, 58, 71, 74, 76, 79, 83 

DMP-105 75 

Donkey King 13 

Donkey Kong 12 

DOS64.CC 41 

Dot Matrix Printer 75 


double speed poke 38, 39 

Dr. Preble 13, 26 

Dragon Computer 12, 13, 14, 15, 34 

Dragonfly Writing 16 

DRAM 37, 82 

Drive Step Rate 39 

DSL 10 

DunkeyMunkey 12 

Dyna Spell 101 

Dynamic ColorNews 14, 16, 18, 21 

Dynamic Electronics 14, 21, 84 

Dynamic RAM 82 

DynaStar 101 


E board 9, 38, 82 

echo mail 60 

editor/assembler 9 

EDTASM 46, 86 

EGA 69 

Eigen Systems 8, 10, 12 

Electronic Audio Recognition System (EARS) 1 6 

Eliminator 20 

Elite Calc 13 

EliteSoftware 13, 14 

Endicott 12 

England 34, 55 

EPROM 11, 42 

Epson 75 


Eversoft Games 56 

Exatron 8, 9, 10, 70 

EXECs 40 

Expansion Devices 76 

Expansion interface 12, 24 

Express Order 5 1 

Extended ADOS-3 21 

Extended Color BASIC (ECB) 37,38,81 

extended keyboard 85 

Falsoft 24, 29, 31, 50, 59, 105 

FARNASystems 29,47,50,56,58,69,77,80,86,89,99,104 

Dan Famsworth 99 

FD-502 72 

Federal Communications Commission, US (FCC) 8, 12 

Mickey Ferguson 7 

FHL 18, 26, 34 

FIDO 52, 60 

Final Fix 93 

FLEX 8, 9, 10, 12, 101, 102 

ArtFlexser 17, 41, 86 

FlightSimll 24 

FORTH 10, 19, 44, 50 

FORTH Interest Group 46 

FORTH09 19, 46, 50 

Frank Hogg Labrotories (FHL) 18,20,26,28,36,38, 101 

Fred Scerbo 8 

French 22 

Gale Force Enterprises 30, 86 

Bill Gates 8 

genealogy 104 

General Electric Network (GENie) 59 

General Videotex Corp (Delphi) 59 

George Associates 10, 11 

Germany 55 

Getting Started with COLOR BASIC 6 

GIME 16, 28, 34, 36, 76, 77, 78, 83, 90, 93 

GIMIX 12, 102 

GlensideCoCoClub 18, 29, 51, 57 

MartyGoodman 14, 22, 24, 25, 26, 58, 88 


Granite Computer Systems 56, 99 

Grantham Software 15 

Graphicom 14 

Graphicomll 15 

Graphics Interrupt Memory Enhancer 1 6 

Gravity Studios 22, 24 

Great Britain 34, 55 

Wayne Green 7, 10, 13 

Green Mountain Micro 41 

Green Thumb 6 

Greg-E-Term 58 

EdGresick 26, 99 

Scott Griepentrogg 23 

JohnGriffen 8, 9 

GUI 50 

GW-BASIC 43, 104 


F board 12, 38, 82 

F&D Associates 7, 8, 11 

LonnieFalk 8, 12, 18, 20, 22, 26, 30, 31 

MikeHaaland 86 

Ham Radio 16 

Hard Disk Interface, Tandy 73 

Hard Drive 14, 16, 17, 18, 20, 73, 74, 79 

hard drive controller 76 

Hard Drive Specialist 71 

HardSoft 56, 74 

hardware key 19 

Ed Hathaway 28 

Chris Hawkes 22 

Hawksoft 56, 84 

HD6309 29, 30, 47, 85, 89, 91, 99 

Tandy's Little Wonder 

page 133 

Hewlett-Packard 45 

hexadecimal numbers 47 

Hi-Res Joystick Interface 80 

History, CoCo (of the) 22 

Hitachi 29, 47, 85, 99 

HJL 14, 84 

FrankHogg 7, 10, 12, 15, 22, 24, 26, 27, 28, 101 

Richard Hogg 101 

Holland 98 

Home Computer Systems, Inc 10 

Home Publisher 19, 20 

HOTCoCo 13, 84 

HowardMedical 18, 22, 25, 26, 29, 79 

HP Books 43 


JimHutchins 27 

Don Hutchison 19 

Hyper I/O 74 


IBM Computers 19, 20, 24, 27, 29, 36, 37, 43, 68, 72, 74, 

80, 103, 104 
Illustrated Memory Banks 8 
Infinitum Technologies 31, 44, 56 
ink-jet printer 76 
Intellevision 5 
IntelUtronics 12 

Interactive Media Systems (IMS) 23,24,25,26,27,28, 102 
Internet 61 
interrupts 49, 78 
InterTAN 20, 21 
VIP Writer III 18 

J&M Systems 13, 16, 17, 20, 41, 71, 76, 79 

J- Windows 103 

Japan 55, 86 

Jarb Software 8 

JDOS 41, 71 

JFDdiskcontroUer 13 

D.P.Johnson 19 

M.David Johnson 44 

AlJost 101 

Joysticks 10, 13, 80 

JPC Products Co. 12 

EdJuge 21 

JWT Enterprises 20, 30, 56, 99 


Kbus 36, 102 

K- Windows 103 

SydKahn 8 

Kala Software 25, 28, 56, 81 

KenKalish 7, 12 

Ken Kaplan 102 

Kaypro 86 

Randy Keippner 99 

Dave Kelly 52 

Ken-Ton 74 

Kenneth-Leigh Enterprises 20, 22, 23 

Kemighan and Ritchie 44 

page 134 

keyboard 13, 14, 15, 20, 35, 82, 84, 91 

keyboard. Dragon 3 5 

keyboard extender 84 

KeyTronic 14, 84 

Kiml 101 

DennisKitsz 9, 10, 14, 15, 41, 42 

Kix30 103 

L.Todd Knudsen 39 

Korea 12, 15, 34, 37, 83, 96 

Kraft 10, 80 

Ron Krebs 7 

CarlKreider 30 

L.R. Tech 16 

Dave Lagerquist 8, 9 

Don Lancaster 66 

Brian Lantz 79 

laserprinter 17, 76 

Kerry Leichtman 13 

Dennis Lewandowski 7, 15 

Library 63 

lightgun 17, 19 

Line Printer 75 

listserv 61 


Logic Probe 89 

LOGO 12, 44, 100, 101 

lower-case board, kit 9, 11, 41 

lowercase, CoCo 2B 40 

Lucas Industries 2000 26 

Lyra 81 


M/L 43 

machine language (M/L) 43, 46 

MACRO-80C 11, 47 

magazines 63 

Magnavox 68 

Maple Leaf Systems 1 1 

Mark Data 7, 8, 9, 13, 14, 18, 84 

Martin Consulting 10 

Marty ' s N ightmare 24 

Marysville 52 

Max-10 19 

MC-10 13, 14 

MC1488 94 

MC1489 94 

MC6800 101 

MC68000 25, 27, 36, 44 

MC68020 23, 24, 28 

MC68030 103 

MC6808 6 

MC6809 6,7, 9, 23, 28, 29, 34, 36, 48, 71, 85, 89, 90, 91 

MC6821(PIA) 91 

MC6822(PIA) 91 

MC6847(VDG) 6, 43, 92 

MC6847-TI (VDG) 15, 92 

MC6883(SAM) 6, 12, 88, 92 

MC74LS283 (SAM)) 92 

MC74LS285 (SAM) 37, 88, 92 

David McNally 17, 24, 100 

Med Systems Software 12, 13 

Tandy's Little Wonder 

MediaLink Software 56 

OlafMeding 44, 46 

Memory Management Unit 83 

Meteor Storni 8 

Dave Meyers 29 

Kent Meyers 8 

Mickey-Term 58 

Micro Technical Products 1 1 

Micro Works 7, 9, 11, 13, 14, 15, 20, 80 

Micro-Leamingware 8 

Microcom 14, 18, 19, 21, 22, 26, 27, 28 

Micronix Systems 13, 84 

Microsoft 6, 8, 38, 42 

Microware 11, 14, 27, 29, 38, 42, 47, 48, 50, 102 

Micro Works 21 

Mid America CoCoFest 52, 57 

Mid Iowa & Country CoCo Club 52, 57 

MIDI 81 

Mini Controller 71 

Jorge Mir 7, 8, 9 

TomMix 7, 13, 15 


MM/1 23, 25, 26, 27, 28, 31, 102, 104 

Mnemonic Instruction Code (M/L) 46 

Model III 6 

Model IV 86 

Modem 57 

Modem Pak 19, 76 

Modifications 81 


Monkey Kong 12 

monochrome monitor 65 

monochrome composite video signal 90 

Charles Moore 44 

Moreton Bay 1 5 

Graham Morphett 98 

Mo ses Engineering 10 

MOTD (Message of the Day) 30, 52, 100 

Motorola 6, 12, 44, 85, 88 

Mouse 17, 36, 80 

MS-DOS 24, 27, 29, 30, 50 

MSB 12 

MSB Electronics 9 

Multi Sync 69 

Multi-Pak Interface (MPI) 12, 14, 21, 27, 72, 76, 95 

Multi-Pak Interface (MPI) Upgrade 77 

multi-tasking 49 

multi-user 49 

Multi- Vue 21, 50 

Multimeter 89 

Multisync 68 

MusicWare 81 

Dave Myers 31, 99 

mylarribbon cable 91 


NANOS Systems 1 1 

National OS-9 UserGroup, Australia 98 

National Science Foundation 6 1 

National Weather Service 6 

Bob Nay 7, 9 

NC board 38 

NEC 68 

Nelson Software 5, 8, 10, 11, 14, 16 

Network 59, 60 

Network 2 101 

New Zealand 98 

Newspaper 09 27 

Newspaper Plus 20 

newsstands 26 


nibble 47 

Night ofthe Living Dead 19 

Nine-Times 20, 30 

NitrOS9 30 

NMOS 85 

NMSA computer group 24 

no-halt 71 

Bill & Sara Nolan 15 


Norway 55 


numeric keypad 15 


Oblique Triad 21, 22 

Steve Odneal 6, 8, 16 

Orchestra 90 80 

OrionTechnologies 19, 21, 22, 79 

orphanware 52 

OS-9 11,12, 14, 16, 17, 19,20,21, 23, 25, 26,27, 30, 34, 36, 38, 44, 

46, 47, 48, 52, 56, 57, 58, 70, 71, 73, 74, 81, 83, 84, 94, 98, 

99, 101, 102 
OS-9 Community Network 52 
OS-9 Underground 30, 31, 99 
OS-9 Users Group (US) 14, 16, 30, 52, 99, 100 
OS-9/68000 (OSK) 23, 56, 99 
OSK'er 23, 24, 26, 27 
Steve Ostrom 27 
Owl-Ware 16, 17, 20, 22, 24, 56, 74 

P&M Products 23 

P-51 Mustang AttackFlight Simulator 15 

Pac Attack 10 


Pacific Northwest CoCoFest 57 

PageMaker 105 

PAL (MPI) 95, 96 

parallel port 76 

PASCAL 9, 14, 44 

Pascal 50 

pathlist 49 

PBJ 13 

PCjr (IBM) 37 


PCM 22, 29, 59 

Kevin Pease 102 


Peripheral Technologies 25 

Peripherals 65 

PeterDibble 14 

Andrew Phelps 7, 9 

Phillips/Signetics 28 

PIA 90, 91 

Tandy's Little Wonder 

page 135 

pipes 48 

PistolGrip Joystick 80 

Boisy Pitre 30 

Platinum Software 12 

Plug 'N Power 43, 80 

Pocket Computer 6 

Tony Podraza 5 1 



Port O' CoCo Users Group 57 

Port Orchard 57 

Portable CoCo 16 

Power Supply 95 

PowerBoost 29 

Prickly-Pear Software 11, 15 

PRINT® 43 

printer 37 


printer, parallel 74 

printer ribbons 75 

printer, serial 74 

Printers 74 

process 48 

Programmers Institute 1 

PT68K 27, 99, 102 

Public Domain 46 

DalePuckett 11, 14, 16, 101 

Dale and Esther Puckett 22 

Bob Puppo 36 

QT 102 
QT+ 102 
QT-30 103 
QT-30-16 103 
QT20 102 
QT20X 102 


R.G.S. Micro Electronics 16 

Radio Shack 5, 6, 9, 10, 12, 13, 14, 15, 26, 32, 51, 70, 74, 89 
Radio Shack BASIC 19 

The Rainbow Magazine 5,11,13,16,17,18,19, 20,21,23,24, 
25, 26, 27, 28, 29, 31, 58, 59, 63, 82, 84, 98, 101, 102, 104 
Rainbow On Disk 16 
Rainbow On Tape 1 1 
Rainbow Scoreboard 13 

RainbowFest 12, 13, 14, 15, 16, 18,20,21,22,23,26,42, 102 
RAM 82 
RAM disk 84 
RAMdisk 50 

Rascan Video Digitizer 21, 80 
Cal Rasmusen 8 
WesRatcliff 47 
RCIS 61 
real-time clock 12 
REMarkable Software 7 
Seigfred (Fred) Remin 98, 99 
repackage 86 
repair kit 89 
Repairs 88 
resolution 65 
Reverse Pohsh Notation 45 

Revision numbers 82 

RFI 8, 38, 70 

RGB 65, 68 

RGB monitor 1 6 (see Analog RGB Monitor) 


RGS Micro Electronics 15 

RickUUand 86 

Rick's Computer Enterprises 25, 57, 99 

robot 15 

ROM 37, 69, 81 

ROM into RAM 38 

ROMPak 6, 8, 22, 69, 76, 78, 79 

Bob Rosen 7, 10, 11, 13, 15 

C.J.Roslund 9 

RS-232 94 

RS-232Pak 19, 57, 58, 76, 78, 94 

RS-DOS 70 

S66470 28 

S68070 24, 28, 36 

Saguaro Software 18 

SALT 96 

SAM 6, 12, 37, 90, 92 

Sampo Color Computer 12, 34 

San Bernardino 52 

Alfredo Santos, 34 

Sardis Technologies 71 

SASI 74 

Hunter Scales 7 

Scandinavia 55 

Fred Scerbo 8 

Screen Play 1 3 

Scripsit 104 

SCSI 16, 74 

SD Enterprises 18, 19, 20, 26 

SDS80C 9 

Seal of Certification 1 1 

PaulSearby 19 

SecondCity 28 

SecondCity Software 20, 25 

SEGA 17 

Seikosha 75 

serial/parallel converter 76 

service manual 88 

Sesame Street 14 

GilShattuck 99 

shell 48 

AlanSheltra 29, 30, 99 

Shugart 72 

Shugart Associates System Interface 74 

BillSias 7, 12 

SIG 59 

Signetics 24, 28 

Terry Simons 52 

SimplyBetter 20, 22, 27, 105 

Simply Better Software 20 

Sinclair 37, 104 

Slot Pack 25 

SlotPak 22, 72, 79 

Small Computer System Interface 74 

Jim Smith 42 

Mike Smith 103 

page 136 

Tandy's Little Wonder 

Snake Mountain Software 1 1 

Soft Sector Marketing 9, 14 

Softgold 98 

Softlaw Corporation 14, 15, 16, 18 

software amnesty 14 

Software Support 14, 73 

Solderwick 89 

Soldering 89 

SONY 68 

Sound/Speech Cartridge 80 

South West Technical Products Company 101 

sparklies 93 

Tom Spear 101 

Spectra 3 24 

Spectral Associates 7, 9, 14, 16 

Spectro Systems 17, 21, 39, 57, 86, 101 

Spectrogram 16 

SpectrumProjects 11, 12, 15, 17, 18, 84 

speech synthesizer 25 

Speech Systems 1 6 

Speech-Sound Pak 76 

Spell'NFix 11 

Spell Test 101 

Mike Spit 102 

SS-50 101 

stack 45 

Peter Stark 13, 14, 99 


Star-Kits 7, 11, 12, 14 

Start OS-9 20 

static 89 

StG Computers, Inc. 23, 26 

StGNet 61 

Strawberry Software 8 

Stringy Floppy 70 

Sugar Software 10, 11, 14 

Sundog 28, 99 

Sundog Systems 18, 20, 21, 24, 57 

Super Color Temiinal 1 1 

SuperColorLibrary 14 

Super Color Writer 11, 14 

SuperControUer 16, 71 

SuperControllerll 71 

Super Extended Color BASIC 16, 37, 38, 42 

SuperComm 58 

SuperiorGraphics 1 1 

F.G.Swygert 39, 86, 104 

Synchronous Address Multiplexer (SAM, see) 6, 92 

SystemlV 25, 27, 99 

T&D Software 58 

T/S1500 104 

tabloid 28 

Tallgrass 8 

Tallgrass Technologies 7, 8, 9, 10 

Tandon 72 

TandyCorp. 6,9,11,15,16,18,19,20,21,24,26,36,37,38,41, 

42,46, 50, 51, 58, 59, 66, 68, 69, 70, 71, 74, 101 
Tandy 2000 73 
Tandy Customer Service 5 1 
Tandy Hardware Support 5 1 
Tandy National Parts 51, 77, 88 

Tano Microcomputer Products Corp. 14, 15, 34 

Tape, high speed 70 

Tape Recorder 69 

tapes, short 70 

TC70 23, 24, 27, 36, 103 

TC9 23, 24, 27, 28, 34, 36, 102 

TDPIOO 12, 82 

TEAC 71, 72 

TEC 72 

Technical Systems Consultants 101 

Teknika 68 

Telecommunications 57 

Telewriter 10, 11 

Telewriter 128 18 

Telewriter 64 12, 18, 84 

Texas Instruments 37 

TextproIV 17 

The Ark 9 


The MC6809 Cookbook 6 

The Netherlands 55 

the Rat 17 

TheSolution 11, 12 

The Trading Post 57 

The Works 20 

thennal printer 75 

Barry Thompson 9 

Three Stooges 42 

TI99/4A 104 

Tiger 27, 36 

Timex 37, 104 

Tokyo Electric Company (TEC) 72 

Tom Mix 10, 15 

Tomcat 23, 24, 28, 36 

tools 89 

TP-10 75 

trackball 13 

Transformation Technologies 9 

TRC 10 

Troubleshooting 89 

TRS-80 5, 6, 9, 43, 65, 100 

TRS-80 Computing 17, 24, 100 

TRS-80 Microcomputer News 6, 9, 15 

TRS-90 6 

Tucson, Arizona 52 

TV 65, 90 


RickUUand 48, 86 
UltimaTemi 58 
UltiMusEIII 81 
UltiMusE/K 81 
Ultralace 26, 29 
Undercolor 15, 16 
Uni-Quad 102 
University of Kentucky 6 
UNIX 24, 27, 44 
Upgrades 8 1 
UpTime 30, 31 
User Groups 5 1 

vaporware a 
Tandy's Little Wonder 

page 137 

VDG 15, 43. 90. 92 
Vendors 56 
BillVergona 30 
VGA 69, 104 
Video Display Devices 65 
video signal 90 
video tape 25 
Videotex 6, 7, 8, 9 
VIPCalcm 20 
VIP Database 19 
VlPUbraiy 14 
VIP Writer m 19 
voicerecognition 16 
VSC 28 
VT-100 27 


Walt Disney 14 

Nancy Ward 52 

Paul K. Ward 26. 27,102 

Dr. Carl Wanen 6 

WasatchWare 43 

Washington ComputCT Services 12 

Wayne Technology 14 

Dennis Weide 22 

West Coast Computer Fair 10 

Western Digital DiskControllerChips 94 

Whitesmith 15 

WICO 13 

DonWilliams 7 

Greg Wilson 98 

Window Master 19 

Window Writer 20, 22 

windows 19, 49 

Mike Wolf 8, 9 

WOLFBUG monitor 8, 9 

Word Power 18, 19, 22 

word processor 10 

world of 68' micros, the 31, 59, 105 

Worlds of Flight 15 

X-10 80 
XC80652P 92 
XPander 79, 87 
XPort 21. 72, 79 

Y cable 79 
Y-Box 79, 87 

Z-80 9, 10, 14 

ZAKSUhfD 13 


ZebraSystems 20, 21, 25. 29, 40 

ZX-80 104 

"My Radio Shack Micro Color Computer 
Has Incredible Power and Performance." 

It's easy to start computins with 
the new Model MC-10 from Radio 
Shack. Affordable, too. Only 

"Don't let the price fool you, this 
is no toy." The MC-10 is a real com- 
puter with over 4000 characters of 
expandable internal memory. Use 
our ready-to-run software or learn 
to prosram in our popular Micro 
Color BASIC. 

"With the touch of a few keys, I 
can create spectacular color 
graphics." And sound effects too! 
Ei3ht vivid colors come alive on 
your TV screen. And the mC-1 has 
a 47-key typewriter-style keyboard 
with real keys — not just a printed 
plastic overlay 

"Imaainc the incredible learning 
potential of this powerful com- 
puter!" Whether you're a tieginner 
or a serious computer hobbyist, 
the MC-10 wont leave you short. 
It features 16 lines of 32 upper 
case characters, a cassette port, 
and a serial port. Add our option- 
al modem and software and 
access news and information 
from CompuServe* or Dow Jones 
News/Retrieval". You can 
even add a printer For 
larger applications, just ^ 

plu3-in our optional 'is^ 

16K RAM Module 'wit*. 

(26-301 3 S49.95) tor an Tji 

additional 16,000 char- ^f^ 

acters of memory i 

"Be prepared (or the future." The 
computer age we once only read 
about IS now upon us. Find out 
how simple and uncomplicated us- 
ing a computer can be with the ■ 
MC-10. Our comprehensive 133- 
page tutorial manual is written to 
get the beginner started fast. 

"I can depend on Radio Shack's 
nationwide sales and service." 
Stop by your nearest Radio Shack 
Computer Center, participat- 
ing store or dealer and ask 
V to see the all-new TRS-80 

■' Micro Color Computer 

I (Cat NO 26-3011). 

—Isaac Asimov 
Renowned Science and 
Science Fiction Author 

The bigsest name in little camput«r<' 


•""^ D Plca£« kikJ me more 
Information on the TTlS-80 MC-10. 


M«<l To Radio ShAck, Ocpl a4-A-<>00 
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page 138 

Tandy's Little Wonder 





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Tandy's Little Wonder 

page 139 














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page 140 

Tandy's Little Wonder